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<ul class="current"><li class="toctree-l1"><a class="reference internal" href="../introduction.html">Introduction</a><ul><li class="toctree-l2"><a class="reference internal" href="../tutorial/getting-started.html">Getting Started</a></li><li class="toctree-l2"><a class="reference external" href="https://docs.atlas.mongodb.com/getting-started/">Create an Atlas Free Tier Cluster</a></li><li class="toctree-l2"><a class="reference internal" href="../core/databases-and-collections.html">Databases and Collections</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/views.html">Views</a></li><li class="toctree-l3"><a class="reference internal" href="../core/materialized-views.html">On-Demand Materialized Views</a></li><li class="toctree-l3"><a class="reference internal" href="../core/capped-collections.html">Capped Collections</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/document.html">Documents</a></li><li class="toctree-l2"><a 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on Debian</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-debian-tarball.html">Install using .tgz Tarball</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-suse.html">Install on SUSE</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-suse-tarball.html">Install using .tgz Tarball</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-amazon.html">Install on Amazon</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-amazon-tarball.html">Install using .tgz Tarball</a></li></ul></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/install-mongodb-enterprise-on-os-x.html">Install on macOS</a></li><li class="toctree-l3"><a class="reference internal" 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class="toctree-l3"><a class="reference internal" href="../core/query-plans.html">Query Plans</a></li><li class="toctree-l3"><a class="reference internal" href="../core/query-optimization.html">Query Optimization</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/evaluate-operation-performance.html">Evaluate Performance of Current Operations</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/optimize-query-performance-with-indexes-and-projections.html">Optimize Query Performance</a></li><li class="toctree-l4"><a class="reference internal" href="../core/write-performance.html">Write Operation Performance</a></li><li class="toctree-l4"><a class="reference internal" href="explain-results.html">Explain Results</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/analyze-query-plan.html">Analyze Query Performance</a></li><li class="toctree-l3"><a class="reference internal" href="../core/tailable-cursors.html">Tailable Cursors</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../aggregation.html">Aggregation</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/aggregation-pipeline.html">Aggregation Pipeline</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/aggregation-pipeline-optimization.html">Aggregation Pipeline Optimization</a></li><li class="toctree-l3"><a class="reference internal" href="../core/aggregation-pipeline-limits.html">Aggregation Pipeline Limits</a></li><li class="toctree-l3"><a class="reference internal" href="../core/aggregation-pipeline-sharded-collections.html">Aggregation Pipeline and Sharded Collections</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/aggregation-zip-code-data-set.html">Example with ZIP Code Data</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/aggregation-with-user-preference-data.html">Example with User Preference Data</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/map-reduce.html">Map-Reduce</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/map-reduce-sharded-collections.html">Map-Reduce and Sharded Collections</a></li><li class="toctree-l3"><a class="reference internal" href="../core/map-reduce-concurrency.html">Map-Reduce Concurrency</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/map-reduce-examples.html">Map-Reduce Examples</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/perform-incremental-map-reduce.html">Perform Incremental Map-Reduce</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/troubleshoot-map-function.html">Troubleshoot the Map Function</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/troubleshoot-reduce-function.html">Troubleshoot the Reduce Function</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="aggregation.html">Aggregation Reference</a><ul><li class="toctree-l3"><a class="reference internal" href="../meta/aggregation-quick-reference.html">Aggregation Pipeline Quick Reference</a></li><li class="toctree-l3"><a class="reference internal" href="operator/aggregation/interface.html">Aggregation Commands</a></li><li class="toctree-l3"><a class="reference internal" href="aggregation-commands-comparison.html">Aggregation Commands Comparison</a></li><li class="toctree-l3"><a class="reference internal" href="aggregation-variables.html">Variables in Aggregation Expressions</a></li><li class="toctree-l3"><a class="reference internal" href="sql-aggregation-comparison.html">SQL to Aggregation Mapping Chart</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../data-modeling.html">Data Models</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/data-modeling-introduction.html">Data Modeling Introduction</a></li><li class="toctree-l2"><a class="reference internal" href="../core/schema-validation.html">Schema Validation</a></li><li class="toctree-l2"><a class="reference internal" href="../core/data-models.html">Data Modeling Concepts</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/data-model-design.html">Data Model Design</a></li><li class="toctree-l3"><a class="reference internal" href="../core/data-model-operations.html">Operational Factors and Data Models</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../applications/data-models.html">Data Model Examples and Patterns</a><ul><li class="toctree-l3"><a class="reference internal" href="../applications/data-models-relationships.html">Model Relationships Between Documents</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-embedded-one-to-one-relationships-between-documents.html">Model One-to-One Relationships with Embedded Documents</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-embedded-one-to-many-relationships-between-documents.html">Model One-to-Many Relationships with Embedded Documents</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-referenced-one-to-many-relationships-between-documents.html">Model One-to-Many Relationships with Document References</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../applications/data-models-tree-structures.html">Model Tree Structures</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-tree-structures-with-parent-references.html">Model Tree Structures with Parent References</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-tree-structures-with-child-references.html">Model Tree Structures with Child References</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-tree-structures-with-ancestors-array.html">Model Tree Structures with an Array of Ancestors</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-tree-structures-with-materialized-paths.html">Model Tree Structures with Materialized Paths</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-tree-structures-with-nested-sets.html">Model Tree Structures with Nested Sets</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../applications/data-models-applications.html">Model Specific Application Contexts</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-data-for-atomic-operations.html">Model Data for Atomic Operations</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-data-for-keyword-search.html">Model Data to Support Keyword Search</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-data-for-schema-versioning.html">Model Data for Schema Versioning</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-monetary-data.html">Model Monetary Data</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-time-data.html">Model Time Data</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/model-computed-data.html">Model Computed Data</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="data-models.html">Data Model Reference</a><ul><li class="toctree-l3"><a class="reference internal" href="database-references.html">Database References</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../core/transactions.html">Transactions</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/transactions-in-applications.html">Drivers API</a></li><li class="toctree-l2"><a class="reference internal" href="../core/transactions-production-consideration.html">Production Considerations</a></li><li class="toctree-l2"><a class="reference internal" href="../core/transactions-sharded-clusters.html">Production Considerations (Sharded Clusters)</a></li><li class="toctree-l2"><a class="reference internal" href="../core/transactions-operations.html">Transactions and Operations</a></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../indexes.html">Indexes</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/index-single.html">Single Field Indexes</a></li><li class="toctree-l2"><a class="reference internal" href="../core/index-compound.html">Compound Indexes</a></li><li class="toctree-l2"><a class="reference internal" href="../core/index-multikey.html">Multikey Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/multikey-index-bounds.html">Multikey Index Bounds</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/index-text.html">Text Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/specify-language-for-text-index.html">Specify a Language for Text Index</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/avoid-text-index-name-limit.html">Specify Name for <code class="docutils literal"><span class="pre">text</span></code> Index</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/control-results-of-text-search.html">Control Search Results with Weights</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/limit-number-of-items-scanned-for-text-search.html">Limit the Number of Entries Scanned</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/index-wildcard.html">Wildcard Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="index-wildcard-restrictions.html">Wildcard Index Restrictions</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/2dsphere.html"><code class="docutils literal"><span class="pre">2dsphere</span></code> Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/query-a-2dsphere-index.html">Query a <code class="docutils literal"><span class="pre">2dsphere</span></code> Index</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/2d.html"><code class="docutils literal"><span class="pre">2d</span></code> Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/build-a-2d-index.html">Create a <code class="docutils literal"><span class="pre">2d</span></code> Index</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/query-a-2d-index.html">Query a <code class="docutils literal"><span class="pre">2d</span></code> Index</a></li><li class="toctree-l3"><a class="reference internal" href="../core/geospatial-indexes.html"><code class="docutils literal"><span class="pre">2d</span></code> Index Internals</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/calculate-distances-using-spherical-geometry-with-2d-geospatial-indexes.html">Calculate Distance Using Spherical Geometry</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/geohaystack.html"><code class="docutils literal"><span class="pre">geoHaystack</span></code> Indexes</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/build-a-geohaystack-index.html">Create a Haystack Index</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/query-a-geohaystack-index.html">Query a Haystack Index</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/index-hashed.html">Hashed Indexes</a></li><li class="toctree-l2"><a class="reference internal" href="../core/index-properties.html">Index Properties</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/index-ttl.html">TTL Indexes</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/expire-data.html">Expire Data from Collections by Setting TTL</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/index-unique.html">Unique Indexes</a></li><li class="toctree-l3"><a class="reference internal" href="../core/index-partial.html">Partial Indexes</a></li><li class="toctree-l3"><a class="reference internal" href="../core/index-case-insensitive.html">Case Insensitive Indexes</a></li><li class="toctree-l3"><a class="reference internal" href="../core/index-sparse.html">Sparse Indexes</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/index-creation.html">Index Builds on Populated Collections</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/build-indexes-on-replica-sets.html">Build Indexes on Replica Sets</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/build-indexes-on-sharded-clusters.html">Build Indexes on Sharded Clusters</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/index-intersection.html">Index Intersection</a></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/manage-indexes.html">Manage Indexes</a></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/measure-index-use.html">Measure Index Use</a></li><li class="toctree-l2"><a class="reference internal" href="../applications/indexes.html">Indexing Strategies</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/create-indexes-to-support-queries.html">Create Indexes to Support Your Queries</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/sort-results-with-indexes.html">Use Indexes to Sort Query Results</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/ensure-indexes-fit-ram.html">Ensure Indexes Fit in RAM</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/create-queries-that-ensure-selectivity.html">Create Queries that Ensure Selectivity</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="indexes.html">Indexing Reference</a></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../security.html">Security</a><ul><li class="toctree-l2"><a class="reference internal" href="../administration/security-checklist.html">Security Checklist</a></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/enable-authentication.html">Enable Access Control</a></li><li class="toctree-l2"><a class="reference internal" href="../core/authentication.html">Authentication</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/security-users.html">Users</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/create-users.html">Add Users</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/authentication-mechanisms.html">Authentication Mechanisms</a><ul><li class="toctree-l4"><a class="reference internal" href="../core/security-scram.html">SCRAM</a></li><li class="toctree-l4"><a class="reference internal" href="../core/security-x.509.html">x.509</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/configure-x509-client-authentication.html">Use x.509 Certificates to Authenticate Clients</a></li></ul></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/authentication-mechanisms-enterprise.html">Enterprise Authentication Mechanisms</a><ul><li class="toctree-l4"><a class="reference internal" href="../core/kerberos.html">Kerberos Authentication</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/control-access-to-mongodb-with-kerberos-authentication.html">Configure MongoDB with Kerberos Authentication on Linux</a></li><li class="toctree-l5"><a class="reference internal" href="../tutorial/control-access-to-mongodb-windows-with-kerberos-authentication.html">Configure MongoDB with Kerberos Authentication on Windows</a></li><li class="toctree-l5"><a class="reference internal" href="../tutorial/troubleshoot-kerberos.html">Troubleshoot Kerberos Authentication</a></li><li class="toctree-l5"><a class="reference internal" href="../tutorial/kerberos-auth-activedirectory-authz.html">Configure MongoDB with Kerberos Authentication and Active Directory Authorization</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="../core/security-ldap.html">LDAP Proxy Authentication</a><ul><li class="toctree-l5"><a class="reference internal" href="../tutorial/configure-ldap-sasl-activedirectory.html">Authenticate Using SASL and LDAP with ActiveDirectory</a></li><li class="toctree-l5"><a class="reference internal" href="../tutorial/configure-ldap-sasl-openldap.html">Authenticate Using SASL and LDAP with OpenLDAP</a></li><li class="toctree-l5"><a class="reference internal" href="../tutorial/authenticate-nativeldap-activedirectory.html">Authenticate and Authorize Users Using Active Directory via Native LDAP</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="../core/security-ldap-external.html">LDAP Authorization</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/security-internal-authentication.html">Internal/Membership Authentication</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/deploy-replica-set-with-keyfile-access-control.html">Deploy Replica Set With Keyfile Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/enforce-keyfile-access-control-in-existing-replica-set.html">Update Replica Set to Keyfile Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/enforce-keyfile-access-control-in-existing-replica-set-without-downtime.html">Update Replica Set to Keyfile Authentication (No Downtime)</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/rotate-key-replica-set.html">Rotate Keys for Replica Sets</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/deploy-sharded-cluster-with-keyfile-access-control.html">Deploy Sharded Cluster with Keyfile Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/enforce-keyfile-access-control-in-existing-sharded-cluster.html">Update Sharded Cluster to Keyfile Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/enforce-keyfile-access-control-in-existing-sharded-cluster-no-downtime.html">Update Sharded Cluster to Keyfile Authentication (No Downtime)</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/rotate-key-sharded-cluster.html">Rotate Keys for Sharded Clusters</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/configure-x509-member-authentication.html">Use x.509 Certificate for Membership Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/upgrade-keyfile-to-x509.html">Upgrade from Keyfile Authentication to x.509 Authentication</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/rotate-x509-membership-certificates.html">Rolling Update of x.509 Cluster Certificates that Contain New DN</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/authorization.html">Role-Based Access Control</a><ul><li class="toctree-l3"><a class="reference internal" href="built-in-roles.html">Built-In Roles</a></li><li class="toctree-l3"><a class="reference internal" href="../core/security-user-defined-roles.html">User-Defined Roles</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-users-and-roles.html">Manage Users and Roles</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/change-own-password-and-custom-data.html">Change Your Password and Custom Data</a></li><li class="toctree-l3"><a class="reference internal" href="../core/collection-level-access-control.html">Collection-Level Access Control</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/security-transport-encryption.html">TLS/SSL (Transport Encryption)</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-ssl.html">Configure <code class="docutils literal"><span class="pre">mongod</span></code> and <code class="docutils literal"><span class="pre">mongos</span></code> for TLS/SSL</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-ssl-clients.html">TLS/SSL Configuration for Clients</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/upgrade-cluster-to-ssl.html">Upgrade a Cluster to Use TLS/SSL</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-fips.html">Configure MongoDB for FIPS</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/security-encryption-at-rest.html">Encryption at Rest</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-encryption.html">Configure Encryption</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/rotate-encryption-key.html">Rotate Encryption Keys</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/security-client-side-encryption.html">Client-Side Field Level Encryption</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/security-automatic-client-side-encryption.html">Automatic Client-Side Field Level Encryption</a><ul><li class="toctree-l4"><a class="reference internal" href="security-client-side-automatic-json-schema.html">Automatic Encryption Rules</a></li><li class="toctree-l4"><a class="reference internal" href="security-client-side-query-aggregation-support.html">Read/Write Support with Automatic Field Level Encryption</a></li><li class="toctree-l4"><a class="reference internal" href="security-client-side-encryption-appendix.html">Appendix</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/security-explicit-client-side-encryption.html">Explicit (Manual) Client-Side Field Level Encryption</a></li><li class="toctree-l3"><a class="reference internal" href="../core/security-client-side-encryption-key-management.html">Master Key and Data Encryption Key Management</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/manage-client-side-encryption-data-keys.html">Manage Data Encryption Keys</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="security-client-side-encryption-limitations.html">Limitations</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/auditing.html">Auditing</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-auditing.html">Configure Auditing</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-audit-filters.html">Configure Audit Filters</a></li><li class="toctree-l3"><a class="reference internal" href="audit-message.html">System Event Audit Messages</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/security-hardening.html">Network and Configuration Hardening</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/security-mongodb-configuration.html">IP Binding</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-linux-iptables-firewall.html">Configure Linux <code class="docutils literal"><span class="pre">iptables</span></code> Firewall for MongoDB</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-windows-netsh-firewall.html">Configure Windows <code class="docutils literal"><span class="pre">netsh</span></code> Firewall for MongoDB</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/implement-field-level-redaction.html">Implement Field Level Redaction</a></li><li class="toctree-l2"><a class="reference internal" href="security.html">Security Reference</a><ul><li class="toctree-l3"><a class="reference internal" href="system-roles-collection.html"><code class="docutils literal"><span class="pre">system.roles</span></code> Collection</a></li><li class="toctree-l3"><a class="reference internal" href="system-users-collection.html"><code class="docutils literal"><span class="pre">system.users</span></code> Collection</a></li><li class="toctree-l3"><a class="reference internal" href="resource-document.html">Resource Document</a></li><li class="toctree-l3"><a class="reference internal" href="privilege-actions.html">Privilege Actions</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/create-a-vulnerability-report.html">Create a Vulnerability Report</a></li><li class="toctree-l2"><a class="reference internal" href="../appendix/security.html">Appendix</a><ul><li class="toctree-l3"><a class="reference internal" href="../appendix/security/appendixA-openssl-ca.html">Appendix A - OpenSSL CA Certificate for Testing</a></li><li class="toctree-l3"><a class="reference internal" href="../appendix/security/appendixB-openssl-server.html">Appendix B - OpenSSL Server Certificates for Testing</a></li><li class="toctree-l3"><a class="reference internal" href="../appendix/security/appendixC-openssl-client.html">Appendix C - OpenSSL Client Certificates for Testing</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../changeStreams.html">Change Streams</a><ul><li class="toctree-l2"><a class="reference internal" href="../administration/change-streams-production-recommendations.html">Change Streams Production Recommendations</a></li><li class="toctree-l2"><a class="reference internal" href="change-events.html">Change Events</a></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../replication.html">Replication</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/replica-set-members.html">Replica Set Members</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-primary.html">Replica Set Primary</a></li><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-secondary.html">Replica Set Secondary Members</a><ul><li class="toctree-l4"><a class="reference internal" href="../core/replica-set-priority-0-member.html">Priority 0 Replica Set Members</a></li><li class="toctree-l4"><a class="reference internal" href="../core/replica-set-hidden-member.html">Hidden Replica Set Members</a></li><li class="toctree-l4"><a class="reference internal" href="../core/replica-set-delayed-member.html">Delayed Replica Set Members</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-arbiter.html">Replica Set Arbiter</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/replica-set-oplog.html">Replica Set Oplog</a></li><li class="toctree-l2"><a class="reference internal" href="../core/replica-set-sync.html">Replica Set Data Synchronization</a></li><li class="toctree-l2"><a class="reference internal" href="../core/replica-set-architectures.html">Replica Set Deployment Architectures</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-architecture-three-members.html">Three Member Replica Sets</a></li><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-architecture-geographically-distributed.html">Replica Sets Distributed Across Two or More Data Centers</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/replica-set-high-availability.html">Replica Set High Availability</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-elections.html">Replica Set Elections</a></li><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-rollbacks.html">Rollbacks During Replica Set Failover</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../applications/replication.html">Replica Set Read and Write Semantics</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/replica-set-write-concern.html">Write Concern for Replica Sets</a></li><li class="toctree-l3"><a class="reference internal" href="../core/read-preference.html">Read Preference</a><ul><li class="toctree-l4"><a class="reference internal" href="../core/read-preference-tags.html">Tag Sets</a></li><li class="toctree-l4"><a class="reference internal" href="../core/read-preference-staleness.html">maxStalenessSeconds</a></li><li class="toctree-l4"><a class="reference internal" href="../core/read-preference-use-cases.html">Read Preference Use Cases</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/read-preference-mechanics.html">Server Selection Algorithm</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/replica-set-deployment.html">Replica Set Deployment Tutorials</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/deploy-replica-set.html">Deploy a Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/deploy-replica-set-for-testing.html">Deploy a Replica Set for Testing and Development</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/deploy-geographically-distributed-replica-set.html">Deploy a Geographically Redundant Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/add-replica-set-arbiter.html">Add an Arbiter to Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-standalone-to-replica-set.html">Convert a Standalone to a Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/expand-replica-set.html">Add Members to a Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/remove-replica-set-member.html">Remove Members from Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/replace-replica-set-member.html">Replace a Replica Set Member</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/replica-set-member-configuration.html">Member Configuration Tutorials</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/adjust-replica-set-member-priority.html">Adjust Priority for Replica Set Member</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-secondary-only-replica-set-member.html">Prevent Secondary from Becoming Primary</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-a-hidden-replica-set-member.html">Configure a Hidden Replica Set Member</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-a-delayed-replica-set-member.html">Configure a Delayed Replica Set Member</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-a-non-voting-replica-set-member.html">Configure Non-Voting Replica Set Member</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-secondary-into-arbiter.html">Convert a Secondary to an Arbiter</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/replica-set-maintenance.html">Replica Set Maintenance Tutorials</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/change-oplog-size.html">Change the Size of the Oplog</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/perform-maintence-on-replica-set-members.html">Perform Maintenance on Replica Set Members</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/force-member-to-be-primary.html">Force a Member to Become Primary</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/resync-replica-set-member.html">Resync a Member of a Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-replica-set-tag-sets.html">Configure Replica Set Tag Sets</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/reconfigure-replica-set-with-unavailable-members.html">Reconfigure a Replica Set with Unavailable Members</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-chained-replication.html">Manage Chained Replication</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/change-hostnames-in-a-replica-set.html">Change Hostnames in a Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/configure-replica-set-secondary-sync-target.html">Configure a Secondary’s Sync Target</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="replication.html">Replication Reference</a><ul><li class="toctree-l3"><a class="reference internal" href="replica-configuration.html">Replica Set Configuration</a></li><li class="toctree-l3"><a class="reference internal" href="replica-set-protocol-versions.html">Replica Set Protocol Version</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/troubleshoot-replica-sets.html">Troubleshoot Replica Sets</a></li><li class="toctree-l3"><a class="reference internal" href="local-database.html">The <code class="docutils literal"><span class="pre">local</span></code> Database</a></li><li class="toctree-l3"><a class="reference internal" href="replica-states.html">Replica Set Member States</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../sharding.html">Sharding</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/sharded-cluster-components.html">Sharded Cluster Components</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/sharded-cluster-shards.html">Shards</a></li><li class="toctree-l3"><a class="reference internal" href="../core/sharded-cluster-config-servers.html">Config Servers (metadata)</a></li><li class="toctree-l3"><a class="reference internal" href="../core/sharded-cluster-query-router.html">Router (mongos)</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/sharding-shard-key.html">Shard Keys</a></li><li class="toctree-l2"><a class="reference internal" href="../core/hashed-sharding.html">Hashed Sharding</a></li><li class="toctree-l2"><a class="reference internal" href="../core/ranged-sharding.html">Ranged Sharding</a></li><li class="toctree-l2"><a class="reference internal" href="../tutorial/deploy-shard-cluster.html">Deploy a Sharded Cluster</a></li><li class="toctree-l2"><a class="reference internal" href="../core/zone-sharding.html">Zones</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-shard-zone.html">Manage Shard Zones</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/sharding-segmenting-data-by-location.html">Segmenting Data by Location</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/sharding-tiered-hardware-for-varying-slas.html">Tiered Hardware for Varying SLA or SLO</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/sharding-segmenting-shards.html">Segmenting Data by Application or Customer</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/sharding-high-availability-writes.html">Distributed Local Writes for Insert Only Workloads</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/sharding-data-partitioning.html">Data Partitioning with Chunks</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/create-chunks-in-sharded-cluster.html">Create Chunks in a Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/split-chunks-in-sharded-cluster.html">Split Chunks in a Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/merge-chunks-in-sharded-cluster.html">Merge Chunks in a Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/modify-chunk-size-in-sharded-cluster.html">Modify Chunk Size in a Sharded Cluster</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/sharding-balancer-administration.html">Balancer</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-sharded-cluster-balancer.html">Manage Sharded Cluster Balancer</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/migrate-chunks-in-sharded-cluster.html">Migrate Chunks in a Sharded Cluster</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/sharded-cluster-administration.html">Administration</a><ul><li class="toctree-l3"><a class="reference internal" href="../administration/sharded-cluster-config-servers.html">Config Server Administration</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/replace-config-server.html">Replace a Config Server</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/view-sharded-cluster-configuration.html">View Cluster Configuration</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/restart-sharded-cluster.html">Restart a Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/migrate-sharded-cluster-to-new-hardware.html">Migrate a Sharded Cluster to Different Hardware</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/add-shards-to-shard-cluster.html">Add Shards to a Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/remove-shards-from-cluster.html">Remove Shards from an Existing Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/clear-jumbo-flag.html">Clear <code class="docutils literal"><span class="pre">jumbo</span></code> Flag</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/backup-sharded-cluster-metadata.html">Back Up Cluster Metadata</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-sharded-cluster-to-replica-set.html">Convert Sharded Cluster to Replica Set</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-replica-set-to-replicated-shard-cluster.html">Convert a Replica Set to a Sharded Cluster</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-shard-standalone-to-shard-replica-set.html">Convert a Shard Standalone to a Shard Replica Set</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="sharding.html">Sharding Reference</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/sharded-cluster-requirements.html">Operational Restrictions</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/troubleshoot-sharded-clusters.html">Troubleshoot Sharded Clusters</a></li><li class="toctree-l3"><a class="reference internal" href="config-database.html">Config Database</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../administration.html">Administration</a><ul><li class="toctree-l2"><a class="reference internal" href="../administration/production-notes.html">Production Notes</a></li><li class="toctree-l2"><a class="reference internal" href="../administration/production-checklist-operations.html">Operations Checklist</a></li><li class="toctree-l2"><a class="reference internal" href="../administration/production-checklist-development.html">Development Checklist</a></li><li class="toctree-l2"><a class="reference internal" href="../administration/analyzing-mongodb-performance.html">Performance</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-the-database-profiler.html">Database Profiler</a><ul><li class="toctree-l4"><a class="reference internal" href="database-profiler.html">Database Profiler Output</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/transparent-huge-pages.html">Disable Transparent Huge Pages (THP)</a></li><li class="toctree-l3"><a class="reference internal" href="ulimit.html">UNIX <code class="docutils literal"><span class="pre">ulimit</span></code> Settings</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/configuration-and-maintenance.html">Configuration and Maintenance</a><ul><li class="toctree-l3"><a class="reference internal" href="../administration/configuration.html">Run-time Database Configuration</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/upgrade-revision.html">Upgrade to the Latest Revision of MongoDB</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-mongodb-processes.html">Manage <code class="docutils literal"><span class="pre">mongod</span></code> Processes</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/terminate-running-operations.html">Terminate Running Operations</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/rotate-log-files.html">Rotate Log Files</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../data-center-awareness.html">Data Center Awareness</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/workload-isolation.html">Workload Isolation in MongoDB Deployments</a></li><li class="toctree-l3"><a class="reference internal" href="../core/zone-sharding.html">Zones</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/manage-shard-zone.html">Manage Shard Zones</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/sharding-segmenting-data-by-location.html">Segmenting Data by Location</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/sharding-tiered-hardware-for-varying-slas.html">Tiered Hardware for Varying SLA or SLO</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/sharding-segmenting-shards.html">Segmenting Data by Application or Customer</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/sharding-high-availability-writes.html">Distributed Local Writes for Insert Only Workloads</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-shard-zone.html">Manage Shard Zones</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/backups.html">MongoDB Backup Methods</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/backup-with-filesystem-snapshots.html">Back Up and Restore with Filesystem Snapshots</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/backup-and-restore-tools.html">Back Up and Restore with MongoDB Tools</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/restore-replica-set-from-backup.html">Restore a Replica Set from MongoDB Backups</a></li><li class="toctree-l3"><a class="reference internal" href="../administration/backup-sharded-clusters.html">Backup and Restore Sharded Clusters</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/backup-sharded-cluster-with-filesystem-snapshots.html">Back Up a Sharded Cluster with File System Snapshots</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/backup-sharded-cluster-with-database-dumps.html">Back Up a Sharded Cluster with Database Dumps</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/schedule-backup-window-for-sharded-clusters.html">Schedule Backup Window for Sharded Clusters</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/restore-sharded-cluster.html">Restore a Sharded Cluster</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/recover-data-following-unexpected-shutdown.html">Recover a Standalone after an Unexpected Shutdown</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../administration/monitoring.html">Monitoring for MongoDB</a><ul><li class="toctree-l3"><a class="reference internal" href="../administration/free-monitoring.html">Free Monitoring</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/monitor-with-snmp.html">Monitor MongoDB With SNMP on Linux</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/monitor-with-snmp-on-windows.html">Monitor MongoDB Windows with SNMP</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/troubleshoot-snmp.html">Troubleshoot SNMP</a></li></ul></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../storage.html">Storage</a><ul><li class="toctree-l2"><a class="reference internal" href="../core/storage-engines.html">Storage Engines</a><ul><li class="toctree-l3"><a class="reference internal" href="../core/wiredtiger.html">WiredTiger Storage Engine</a><ul><li class="toctree-l4"><a class="reference internal" href="../tutorial/change-standalone-wiredtiger.html">Change Standalone to WiredTiger</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/change-replica-set-wiredtiger.html">Change Replica Set to WiredTiger</a></li><li class="toctree-l4"><a class="reference internal" href="../tutorial/change-sharded-cluster-wiredtiger.html">Change Sharded Cluster to WiredTiger</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../core/inmemory.html">In-Memory Storage Engine</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/journaling.html">Journaling</a><ul><li class="toctree-l3"><a class="reference internal" href="../tutorial/manage-journaling.html">Manage Journaling</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../core/gridfs.html">GridFS</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/storage.html">FAQ: MongoDB Storage</a></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../faq.html">Frequently Asked Questions</a><ul><li class="toctree-l2"><a class="reference internal" href="../faq/fundamentals.html">FAQ: MongoDB Fundamentals</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/indexes.html">FAQ: Indexes</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/concurrency.html">FAQ: Concurrency</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/sharding.html">FAQ: Sharding with MongoDB</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/replica-sets.html">FAQ: Replication and Replica Sets</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/storage.html">FAQ: MongoDB Storage</a></li><li class="toctree-l2"><a class="reference internal" href="../faq/diagnostics.html">FAQ: MongoDB Diagnostics</a></li></ul></li><li class="toctree-l1 current"><a class="reference internal" href="../reference.html">Reference</a><ul class="current"><li class="toctree-l2"><a class="reference internal" href="operator.html">Operators</a><ul><li class="toctree-l3"><a class="reference internal" href="operator/query.html">Query and Projection Operators</a><ul><li class="toctree-l4"><a class="reference internal" href="operator/query-comparison.html">Comparison Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/eq.html">$eq</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/gt.html">$gt</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/gte.html">$gte</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/in.html">$in</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/lt.html">$lt</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/lte.html">$lte</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/ne.html">$ne</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/nin.html">$nin</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-logical.html">Logical Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/and.html">$and</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/not.html">$not</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/nor.html">$nor</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/or.html">$or</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-element.html">Element Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/exists.html">$exists</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/type.html">$type</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-evaluation.html">Evaluation Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/expr.html">$expr</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/jsonSchema.html">$jsonSchema</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/mod.html">$mod</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/regex.html">$regex</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/text.html">$text</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/where.html">$where</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-geospatial.html">Geospatial Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/geoIntersects.html">$geoIntersects</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/geoWithin.html">$geoWithin</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/near.html">$near</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/nearSphere.html">$nearSphere</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/box.html">$box</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/center.html">$center</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/centerSphere.html">$centerSphere</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/geometry.html">$geometry</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/maxDistance.html">$maxDistance</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/minDistance.html">$minDistance</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/polygon.html">$polygon</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/uniqueDocs.html">$uniqueDocs</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-array.html">Array Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/all.html">$all</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/elemMatch.html">$elemMatch (query)</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/size.html">$size</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query-bitwise.html">Bitwise Query Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/query/bitsAllClear.html">$bitsAllClear</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/bitsAllSet.html">$bitsAllSet</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/bitsAnyClear.html">$bitsAnyClear</a></li><li class="toctree-l5"><a class="reference internal" href="operator/query/bitsAnySet.html">$bitsAnySet</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/query/comment.html">$comment</a></li><li class="toctree-l4"><a class="reference internal" href="operator/projection.html">Projection Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/projection/positional.html">$ (projection)</a></li><li class="toctree-l5"><a class="reference internal" href="operator/projection/elemMatch.html">$elemMatch (projection)</a></li><li class="toctree-l5"><a class="reference internal" href="operator/projection/meta.html">$meta</a></li><li class="toctree-l5"><a class="reference internal" href="operator/projection/slice.html">$slice (projection)</a></li></ul></li></ul></li><li class="toctree-l3"><a class="reference internal" href="operator/update.html">Update Operators</a><ul><li class="toctree-l4"><a class="reference internal" href="operator/update-field.html">Field Update Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/update/currentDate.html">$currentDate</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/inc.html">$inc</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/min.html">$min</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/max.html">$max</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/mul.html">$mul</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/rename.html">$rename</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/set.html">$set</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/setOnInsert.html">$setOnInsert</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/unset.html">$unset</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/update-array.html">Array Update Operators</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/update/positional.html">$ (update)</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/positional-all.html">$[]</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/positional-filtered.html">$[&lt;identifier&gt;]</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/addToSet.html">$addToSet</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/pop.html">$pop</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/pull.html">$pull</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/push.html">$push</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/pullAll.html">$pullAll</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/each.html">$each</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/position.html">$position</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/slice.html">$slice</a></li><li class="toctree-l5"><a class="reference internal" href="operator/update/sort.html">$sort</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="operator/update-bitwise.html">Bitwise Update Operator</a><ul><li class="toctree-l5"><a class="reference internal" href="operator/update/bit.html">$bit</a></li></ul></li></ul></li><li class="toctree-l3"><a class="reference internal" href="operator/aggregation-pipeline.html">Aggregation Pipeline Stages</a><ul><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/addFields.html">$addFields (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/bucket.html">$bucket (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/bucketAuto.html">$bucketAuto (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/collStats.html">$collStats (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/count.html">$count (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/currentOp.html">$currentOp (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/facet.html">$facet (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/geoNear.html">$geoNear (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/graphLookup.html">$graphLookup (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/group.html">$group (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/indexStats.html">$indexStats (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/limit.html">$limit (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/listLocalSessions.html">$listLocalSessions</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/listSessions.html">$listSessions</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/lookup.html">$lookup (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/match.html">$match (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/merge.html">$merge (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/out.html">$out (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/planCacheStats.html">$planCacheStats</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/project.html">$project (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/redact.html">$redact (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/replaceRoot.html">$replaceRoot (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/replaceWith.html">$replaceWith (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sample.html">$sample (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/set.html">$set (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/skip.html">$skip (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sort.html">$sort (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sortByCount.html">$sortByCount (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/unset.html">$unset (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/unwind.html">$unwind (aggregation)</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="operator/aggregation.html">Aggregation Pipeline Operators</a><ul><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/abs.html">$abs (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/acos.html">$acos (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/acosh.html">$acosh (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/add.html">$add (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/addToSet.html">$addToSet (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/allElementsTrue.html">$allElementsTrue (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/and.html">$and (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/anyElementTrue.html">$anyElementTrue (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/arrayElemAt.html">$arrayElemAt (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/arrayToObject.html">$arrayToObject (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/asin.html">$asin (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/asinh.html">$asinh (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/atan.html">$atan (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/atan2.html">$atan2 (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/atanh.html">$atanh (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/avg.html">$avg (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/ceil.html">$ceil (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/cmp.html">$cmp (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/concat.html">$concat (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/concatArrays.html">$concatArrays (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/cond.html">$cond (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/convert.html">$convert (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/cos.html">$cos (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dateFromParts.html">$dateFromParts (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dateToParts.html">$dateToParts (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dateFromString.html">$dateFromString (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dateToString.html">$dateToString (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dayOfMonth.html">$dayOfMonth (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dayOfWeek.html">$dayOfWeek (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/dayOfYear.html">$dayOfYear (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/degreesToRadians.html">$degreesToRadians (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/divide.html">$divide (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/eq.html">$eq (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/exp.html">$exp (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/filter.html">$filter (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/first.html">$first (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/floor.html">$floor (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/gt.html">$gt (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/gte.html">$gte (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/hour.html">$hour (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/ifNull.html">$ifNull (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/in.html">$in (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/indexOfArray.html">$indexOfArray (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/indexOfBytes.html">$indexOfBytes (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/indexOfCP.html">$indexOfCP (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/isArray.html">$isArray (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/isoDayOfWeek.html">$isoDayOfWeek (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/isoWeek.html">$isoWeek (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/isoWeekYear.html">$isoWeekYear (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/last.html">$last (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/let.html">$let (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/literal.html">$literal (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/ln.html">$ln (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/log.html">$log (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/log10.html">$log10 (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/lt.html">$lt (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/lte.html">$lte (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/ltrim.html">$ltrim (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/map.html">$map (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/max.html">$max (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/mergeObjects.html">$mergeObjects (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/meta.html">$meta (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/min.html">$min (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/millisecond.html">$millisecond (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/minute.html">$minute (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/mod.html">$mod (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/month.html">$month (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/multiply.html">$multiply (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/ne.html">$ne (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/not.html">$not (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/objectToArray.html">$objectToArray (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/or.html">$or (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/pow.html">$pow (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/push.html">$push (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/radiansToDegrees.html">$radiansToDegrees (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/range.html">$range (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/reduce.html">$reduce (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/regexFind.html">$regexFind (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/regexFindAll.html">$regexFindAll (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/regexMatch.html">$regexMatch (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/reverseArray.html">$reverseArray (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/round.html">$round (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/rtrim.html">$rtrim (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/second.html">$second (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/setDifference.html">$setDifference (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/setEquals.html">$setEquals (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/setIntersection.html">$setIntersection (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/setIsSubset.html">$setIsSubset (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/setUnion.html">$setUnion (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/size.html">$size (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sin.html">$sin (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/slice.html">$slice (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/split.html">$split (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sqrt.html">$sqrt (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/stdDevPop.html">$stdDevPop (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/stdDevSamp.html">$stdDevSamp (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/strcasecmp.html">$strcasecmp (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/strLenBytes.html">$strLenBytes (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/strLenCP.html">$strLenCP (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/substr.html">$substr (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/substrBytes.html">$substrBytes (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/substrCP.html">$substrCP (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/subtract.html">$subtract (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/sum.html">$sum (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/switch.html">$switch (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/tan.html">$tan (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toBool.html">$toBool (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toDate.html">$toDate (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toDecimal.html">$toDecimal (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toDouble.html">$toDouble(aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toInt.html">$toInt (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toLong.html">$toLong (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toObjectId.html">$toObjectId (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toString.html">$toString (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toLower.html">$toLower (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/toUpper.html">$toUpper (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/trim.html">$trim (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/trunc.html">$trunc (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/type.html">$type (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/week.html">$week (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/year.html">$year (aggregation)</a></li><li class="toctree-l4"><a class="reference internal" href="operator/aggregation/zip.html">$zip (aggregation)</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="operator/query-modifier.html">Query Modifiers</a><ul><li class="toctree-l4"><a class="reference internal" href="operator/meta/comment.html">$comment</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/explain.html">$explain</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/hint.html">$hint</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/max.html">$max</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/maxTimeMS.html">$maxTimeMS</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/min.html">$min</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/orderby.html">$orderby</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/query.html">$query</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/returnKey.html">$returnKey</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/showDiskLoc.html">$showDiskLoc</a></li><li class="toctree-l4"><a class="reference internal" href="operator/meta/natural.html">$natural</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="command.html">Database Commands</a><ul><li class="toctree-l3"><a class="reference internal" href="command/nav-aggregation.html">Aggregation Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/aggregate.html">aggregate</a></li><li class="toctree-l4"><a class="reference internal" href="command/count.html">count</a></li><li class="toctree-l4"><a class="reference internal" href="command/distinct.html">distinct</a></li><li class="toctree-l4"><a class="reference internal" href="command/mapReduce.html">mapReduce</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-geospatial.html">Geospatial Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/geoSearch.html">geoSearch</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-crud.html">Query and Write Operation Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/delete.html">delete</a></li><li class="toctree-l4"><a class="reference internal" href="command/find.html">find</a></li><li class="toctree-l4"><a class="reference internal" href="command/findAndModify.html">findAndModify</a></li><li class="toctree-l4"><a class="reference internal" href="command/getLastError.html">getLastError</a></li><li class="toctree-l4"><a class="reference internal" href="command/getMore.html">getMore</a></li><li class="toctree-l4"><a class="reference internal" href="command/insert.html">insert</a></li><li class="toctree-l4"><a class="reference internal" href="command/resetError.html">resetError</a></li><li class="toctree-l4"><a class="reference internal" href="command/update.html">update</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-plan-cache.html">Query Plan Cache Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/planCacheClear.html">planCacheClear</a></li><li class="toctree-l4"><a class="reference internal" href="command/planCacheClearFilters.html">planCacheClearFilters</a></li><li class="toctree-l4"><a class="reference internal" href="command/planCacheListFilters.html">planCacheListFilters</a></li><li class="toctree-l4"><a class="reference internal" href="command/planCacheListPlans.html">planCacheListPlans</a></li><li class="toctree-l4"><a class="reference internal" href="command/planCacheListQueryShapes.html">planCacheListQueryShapes</a></li><li class="toctree-l4"><a class="reference internal" href="command/planCacheSetFilter.html">planCacheSetFilter</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-authentication.html">Authentication Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/authenticate.html">authenticate</a></li><li class="toctree-l4"><a class="reference internal" href="command/getnonce.html">getnonce</a></li><li class="toctree-l4"><a class="reference internal" href="command/logout.html">logout</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-user-management.html">User Management Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/createUser.html">createUser</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropAllUsersFromDatabase.html">dropAllUsersFromDatabase</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropUser.html">dropUser</a></li><li class="toctree-l4"><a class="reference internal" href="command/grantRolesToUser.html">grantRolesToUser</a></li><li class="toctree-l4"><a class="reference internal" href="command/revokeRolesFromUser.html">revokeRolesFromUser</a></li><li class="toctree-l4"><a class="reference internal" href="command/updateUser.html">updateUser</a></li><li class="toctree-l4"><a class="reference internal" href="command/usersInfo.html">usersInfo</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-role-management.html">Role Management Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/createRole.html">createRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropRole.html">dropRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropAllRolesFromDatabase.html">dropAllRolesFromDatabase</a></li><li class="toctree-l4"><a class="reference internal" href="command/grantPrivilegesToRole.html">grantPrivilegesToRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/grantRolesToRole.html">grantRolesToRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/invalidateUserCache.html">invalidateUserCache</a></li><li class="toctree-l4"><a class="reference internal" href="command/revokePrivilegesFromRole.html">revokePrivilegesFromRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/revokeRolesFromRole.html">revokeRolesFromRole</a></li><li class="toctree-l4"><a class="reference internal" href="command/rolesInfo.html">rolesInfo</a></li><li class="toctree-l4"><a class="reference internal" href="command/updateRole.html">updateRole</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-replication.html">Replication Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/applyOps.html">applyOps</a></li><li class="toctree-l4"><a class="reference internal" href="command/isMaster.html">isMaster</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetAbortPrimaryCatchUp.html">replSetAbortPrimaryCatchUp</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetFreeze.html">replSetFreeze</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetGetConfig.html">replSetGetConfig</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetGetStatus.html">replSetGetStatus</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetInitiate.html">replSetInitiate</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetMaintenance.html">replSetMaintenance</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetReconfig.html">replSetReconfig</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetResizeOplog.html">replSetResizeOplog</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetStepDown.html">replSetStepDown</a></li><li class="toctree-l4"><a class="reference internal" href="command/replSetSyncFrom.html">replSetSyncFrom</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-sharding.html">Sharding Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/addShard.html">addShard</a></li><li class="toctree-l4"><a class="reference internal" href="command/addShardToZone.html">addShardToZone</a></li><li class="toctree-l4"><a class="reference internal" href="command/balancerStart.html">balancerStart</a></li><li class="toctree-l4"><a class="reference internal" href="command/balancerStatus.html">balancerStatus</a></li><li class="toctree-l4"><a class="reference internal" href="command/balancerStop.html">balancerStop</a></li><li class="toctree-l4"><a class="reference internal" href="command/checkShardingIndex.html">checkShardingIndex</a></li><li class="toctree-l4"><a class="reference internal" href="command/clearJumboFlag.html">clearJumboFlag</a></li><li class="toctree-l4"><a class="reference internal" href="command/cleanupOrphaned.html">cleanupOrphaned</a></li><li class="toctree-l4"><a class="reference internal" href="command/enableSharding.html">enableSharding</a></li><li class="toctree-l4"><a class="reference internal" href="command/flushRouterConfig.html">flushRouterConfig</a></li><li class="toctree-l4"><a class="reference internal" href="command/getShardMap.html">getShardMap</a></li><li class="toctree-l4"><a class="reference internal" href="command/getShardVersion.html">getShardVersion</a></li><li class="toctree-l4"><a class="reference internal" href="command/isdbgrid.html">isdbgrid</a></li><li class="toctree-l4"><a class="reference internal" href="command/listShards.html">listShards</a></li><li class="toctree-l4"><a class="reference internal" href="command/medianKey.html">medianKey</a></li><li class="toctree-l4"><a class="reference internal" href="command/moveChunk.html">moveChunk</a></li><li class="toctree-l4"><a class="reference internal" href="command/movePrimary.html">movePrimary</a></li><li class="toctree-l4"><a class="reference internal" href="command/mergeChunks.html">mergeChunks</a></li><li class="toctree-l4"><a class="reference internal" href="command/removeShard.html">removeShard</a></li><li class="toctree-l4"><a class="reference internal" href="command/removeShardFromZone.html">removeShardFromZone</a></li><li class="toctree-l4"><a class="reference internal" href="command/setShardVersion.html">setShardVersion</a></li><li class="toctree-l4"><a class="reference internal" href="command/shardCollection.html">shardCollection</a></li><li class="toctree-l4"><a class="reference internal" href="command/shardingState.html">shardingState</a></li><li class="toctree-l4"><a class="reference internal" href="command/split.html">split</a></li><li class="toctree-l4"><a class="reference internal" href="command/splitChunk.html">splitChunk</a></li><li class="toctree-l4"><a class="reference internal" href="command/splitVector.html">splitVector</a></li><li class="toctree-l4"><a class="reference internal" href="command/unsetSharding.html">unsetSharding</a></li><li class="toctree-l4"><a class="reference internal" href="command/updateZoneKeyRange.html">updateZoneKeyRange</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-sessions.html">Sessions Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/abortTransaction.html">abortTransaction</a></li><li class="toctree-l4"><a class="reference internal" href="command/commitTransaction.html">commitTransaction</a></li><li class="toctree-l4"><a class="reference internal" href="command/endSessions.html">endSessions</a></li><li class="toctree-l4"><a class="reference internal" href="command/killAllSessions.html">killAllSessions</a></li><li class="toctree-l4"><a class="reference internal" href="command/killAllSessionsByPattern.html">killAllSessionsByPattern</a></li><li class="toctree-l4"><a class="reference internal" href="command/killSessions.html">killSessions</a></li><li class="toctree-l4"><a class="reference internal" href="command/refreshSessions.html">refreshSessions</a></li><li class="toctree-l4"><a class="reference internal" href="command/startSession.html">startSession</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-administration.html">Administration Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/clean.html">clean</a></li><li class="toctree-l4"><a class="reference internal" href="command/cloneCollection.html">cloneCollection</a></li><li class="toctree-l4"><a class="reference internal" href="command/cloneCollectionAsCapped.html">cloneCollectionAsCapped</a></li><li class="toctree-l4"><a class="reference internal" href="command/collMod.html">collMod</a></li><li class="toctree-l4"><a class="reference internal" href="command/compact.html">compact</a></li><li class="toctree-l4"><a class="reference internal" href="command/connPoolSync.html">connPoolSync</a></li><li class="toctree-l4"><a class="reference internal" href="command/convertToCapped.html">convertToCapped</a></li><li class="toctree-l4"><a class="reference internal" href="command/create.html">create</a></li><li class="toctree-l4"><a class="reference internal" href="command/createIndexes.html">createIndexes</a></li><li class="toctree-l4"><a class="reference internal" href="command/currentOp.html">currentOp</a></li><li class="toctree-l4"><a class="reference internal" href="command/drop.html">drop</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropDatabase.html">dropDatabase</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropConnections.html">dropConnections</a></li><li class="toctree-l4"><a class="reference internal" href="command/dropIndexes.html">dropIndexes</a></li><li class="toctree-l4"><a class="reference internal" href="command/filemd5.html">filemd5</a></li><li class="toctree-l4"><a class="reference internal" href="command/fsync.html">fsync</a></li><li class="toctree-l4"><a class="reference internal" href="command/fsyncUnlock.html">fsyncUnlock</a></li><li class="toctree-l4"><a class="reference internal" href="command/getParameter.html">getParameter</a></li><li class="toctree-l4"><a class="reference internal" href="command/killCursors.html">killCursors</a></li><li class="toctree-l4"><a class="reference internal" href="command/killOp.html">killOp</a></li><li class="toctree-l4"><a class="reference internal" href="command/listCollections.html">listCollections</a></li><li class="toctree-l4"><a class="reference internal" href="command/listDatabases.html">listDatabases</a></li><li class="toctree-l4"><a class="reference internal" href="command/listIndexes.html">listIndexes</a></li><li class="toctree-l4"><a class="reference internal" href="command/logRotate.html">logRotate</a></li><li class="toctree-l4"><a class="reference internal" href="command/reIndex.html">reIndex</a></li><li class="toctree-l4"><a class="reference internal" href="command/renameCollection.html">renameCollection</a></li><li class="toctree-l4"><a class="reference internal" href="command/setFeatureCompatibilityVersion.html">setFeatureCompatibilityVersion</a></li><li class="toctree-l4"><a class="reference internal" href="command/setParameter.html">setParameter</a></li><li class="toctree-l4"><a class="reference internal" href="command/shutdown.html">shutdown</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-diagnostic.html">Diagnostic Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/availableQueryOptions.html">availableQueryOptions</a></li><li class="toctree-l4"><a class="reference internal" href="command/buildInfo.html">buildInfo</a></li><li class="toctree-l4"><a class="reference internal" href="command/collStats.html">collStats</a></li><li class="toctree-l4"><a class="reference internal" href="command/connPoolStats.html">connPoolStats</a></li><li class="toctree-l4"><a class="reference internal" href="command/connectionStatus.html">connectionStatus</a></li><li class="toctree-l4"><a class="reference internal" href="command/cursorInfo.html">cursorInfo</a></li><li class="toctree-l4"><a class="reference internal" href="command/dataSize.html">dataSize</a></li><li class="toctree-l4"><a class="reference internal" href="command/dbHash.html">dbHash</a></li><li class="toctree-l4"><a class="reference internal" href="command/dbStats.html">dbStats</a></li><li class="toctree-l4"><a class="reference internal" href="command/diagLogging.html">diagLogging</a></li><li class="toctree-l4"><a class="reference internal" href="command/driverOIDTest.html">driverOIDTest</a></li><li class="toctree-l4"><a class="reference internal" href="command/explain.html">explain</a></li><li class="toctree-l4"><a class="reference internal" href="command/features.html">features</a></li><li class="toctree-l4"><a class="reference internal" href="command/getCmdLineOpts.html">getCmdLineOpts</a></li><li class="toctree-l4"><a class="reference internal" href="command/getLog.html">getLog</a></li><li class="toctree-l4"><a class="reference internal" href="command/hostInfo.html">hostInfo</a></li><li class="toctree-l4"><a class="reference internal" href="command/isSelf.html">isSelf</a></li><li class="toctree-l4"><a class="reference internal" href="command/listCommands.html">listCommands</a></li><li class="toctree-l4"><a class="reference internal" href="command/netstat.html">netstat</a></li><li class="toctree-l4"><a class="reference internal" href="command/ping.html">ping</a></li><li class="toctree-l4"><a class="reference internal" href="command/profile.html">profile</a></li><li class="toctree-l4"><a class="reference internal" href="command/serverStatus.html">serverStatus</a></li><li class="toctree-l4"><a class="reference internal" href="command/shardConnPoolStats.html">shardConnPoolStats</a></li><li class="toctree-l4"><a class="reference internal" href="command/top.html">top</a></li><li class="toctree-l4"><a class="reference internal" href="command/validate.html">validate</a></li><li class="toctree-l4"><a class="reference internal" href="command/whatsmyuri.html">whatsmyuri</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-free-monitoring.html">Free Monitoring Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/getFreeMonitoringStatus.html">getFreeMonitoringStatus</a></li><li class="toctree-l4"><a class="reference internal" href="command/setFreeMonitoring.html">setFreeMonitoring</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="command/nav-auditing.html">System Events Auditing Commands</a><ul><li class="toctree-l4"><a class="reference internal" href="command/logApplicationMessage.html">logApplicationMessage</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="method.html"><code class="docutils literal"><span class="pre">mongo</span></code> Shell Methods</a><ul><li class="toctree-l3"><a class="reference internal" href="method/js-collection.html">Collection Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.collection.aggregate.html">db.collection.aggregate()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.bulkWrite.html">db.collection.bulkWrite()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.copyTo.html">db.collection.copyTo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.count.html">db.collection.count()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.countDocuments.html">db.collection.countDocuments()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.estimatedDocumentCount.html">db.collection.estimatedDocumentCount()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.createIndex.html">db.collection.createIndex()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.createIndexes.html">db.collection.createIndexes()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.dataSize.html">db.collection.dataSize()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.deleteOne.html">db.collection.deleteOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.deleteMany.html">db.collection.deleteMany()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.distinct.html">db.collection.distinct()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.drop.html">db.collection.drop()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.dropIndex.html">db.collection.dropIndex()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.dropIndexes.html">db.collection.dropIndexes()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.ensureIndex.html">db.collection.ensureIndex()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.explain.html">db.collection.explain()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.find.html">db.collection.find()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.findAndModify.html">db.collection.findAndModify()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.findOne.html">db.collection.findOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.findOneAndDelete.html">db.collection.findOneAndDelete()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.findOneAndReplace.html">db.collection.findOneAndReplace()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.findOneAndUpdate.html">db.collection.findOneAndUpdate()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.getIndexes.html">db.collection.getIndexes()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.getShardDistribution.html">db.collection.getShardDistribution()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.getShardVersion.html">db.collection.getShardVersion()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.insert.html">db.collection.insert()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.insertOne.html">db.collection.insertOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.insertMany.html">db.collection.insertMany()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.isCapped.html">db.collection.isCapped()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.latencyStats.html">db.collection.latencyStats()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.mapReduce.html">db.collection.mapReduce()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.reIndex.html">db.collection.reIndex()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.remove.html">db.collection.remove()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.renameCollection.html">db.collection.renameCollection()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.replaceOne.html">db.collection.replaceOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.save.html">db.collection.save()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.stats.html">db.collection.stats()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.storageSize.html">db.collection.storageSize()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.totalIndexSize.html">db.collection.totalIndexSize()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.totalSize.html">db.collection.totalSize()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.update.html">db.collection.update()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.updateOne.html">db.collection.updateOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.updateMany.html">db.collection.updateMany()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.watch.html">db.collection.watch()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.validate.html">db.collection.validate()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-cursor.html">Cursor Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/cursor.addOption.html">cursor.addOption()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.allowPartialResults.html">cursor.allowPartialResults()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.batchSize.html">cursor.batchSize()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.close.html">cursor.close()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.isClosed.html">cursor.isClosed()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.collation.html">cursor.collation()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.comment.html">cursor.comment()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.count.html">cursor.count()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.explain.html">cursor.explain()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.forEach.html">cursor.forEach()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.hasNext.html">cursor.hasNext()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.hint.html">cursor.hint()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.isExhausted.html">cursor.isExhausted()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.itcount.html">cursor.itcount()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.limit.html">cursor.limit()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.map.html">cursor.map()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.max.html">cursor.max()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.maxTimeMS.html">cursor.maxTimeMS()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.min.html">cursor.min()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.next.html">cursor.next()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.noCursorTimeout.html">cursor.noCursorTimeout()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.objsLeftInBatch.html">cursor.objsLeftInBatch()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.pretty.html">cursor.pretty()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.readConcern.html">cursor.readConcern()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.readPref.html">cursor.readPref()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.returnKey.html">cursor.returnKey()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.showRecordId.html">cursor.showRecordId()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.size.html">cursor.size()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.skip.html">cursor.skip()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.sort.html">cursor.sort()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.tailable.html">cursor.tailable()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cursor.toArray.html">cursor.toArray()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-database.html">Database Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.adminCommand.html">db.adminCommand()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.aggregate.html">db.aggregate()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.cloneCollection.html">db.cloneCollection()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.cloneDatabase.html">db.cloneDatabase()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.commandHelp.html">db.commandHelp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.copyDatabase.html">db.copyDatabase()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.createCollection.html">db.createCollection()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.createView.html">db.createView()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.currentOp.html">db.currentOp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.dropDatabase.html">db.dropDatabase()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.eval.html">db.eval()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.fsyncLock.html">db.fsyncLock()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.fsyncUnlock.html">db.fsyncUnlock()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getCollection.html">db.getCollection()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getCollectionInfos.html">db.getCollectionInfos()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getCollectionNames.html">db.getCollectionNames()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getLastError.html">db.getLastError()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getLastErrorObj.html">db.getLastErrorObj()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getLogComponents.html">db.getLogComponents()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getMongo.html">db.getMongo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getName.html">db.getName()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getProfilingLevel.html">db.getProfilingLevel()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getProfilingStatus.html">db.getProfilingStatus()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getReplicationInfo.html">db.getReplicationInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getSiblingDB.html">db.getSiblingDB()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.help.html">db.help()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.hostInfo.html">db.hostInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.isMaster.html">db.isMaster()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.killOp.html">db.killOp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.listCommands.html">db.listCommands()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.logout.html">db.logout()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.printCollectionStats.html">db.printCollectionStats()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.printReplicationInfo.html">db.printReplicationInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.printShardingStatus.html">db.printShardingStatus()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.printSlaveReplicationInfo.html">db.printSlaveReplicationInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.resetError.html">db.resetError()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.runCommand.html">db.runCommand()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.serverBuildInfo.html">db.serverBuildInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.serverCmdLineOpts.html">db.serverCmdLineOpts()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.serverStatus.html">db.serverStatus()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.setLogLevel.html">db.setLogLevel()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.setProfilingLevel.html">db.setProfilingLevel()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.shutdownServer.html">db.shutdownServer()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.stats.html">db.stats()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.version.html">db.version()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.watch.html">db.watch()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-plan-cache.html">Query Plan Cache Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.collection.getPlanCache.html">db.collection.getPlanCache()</a></li><li class="toctree-l4"><a class="reference internal" href="method/PlanCache.clear.html">PlanCache.clear()</a></li><li class="toctree-l4"><a class="reference internal" href="method/PlanCache.clearPlansByQuery.html">PlanCache.clearPlansByQuery()</a></li><li class="toctree-l4"><a class="reference internal" href="method/PlanCache.getPlansByQuery.html">PlanCache.getPlansByQuery()</a></li><li class="toctree-l4"><a class="reference internal" href="method/PlanCache.help.html">PlanCache.help()</a></li><li class="toctree-l4"><a class="reference internal" href="method/PlanCache.listQueryShapes.html">PlanCache.listQueryShapes()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-bulk.html">Bulk Operation Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.collection.initializeOrderedBulkOp.html">db.collection.initializeOrderedBulkOp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.collection.initializeUnorderedBulkOp.html">db.collection.initializeUnorderedBulkOp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.html">Bulk()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.execute.html">Bulk.execute()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.html">Bulk.find()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.arrayFilters.html">Bulk.find.arrayFilters()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.collation.html">Bulk.find.collation()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.hint.html">Bulk.find.hint()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.remove.html">Bulk.find.remove()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.removeOne.html">Bulk.find.removeOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.replaceOne.html">Bulk.find.replaceOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.updateOne.html">Bulk.find.updateOne()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.update.html">Bulk.find.update()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.find.upsert.html">Bulk.find.upsert()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.getOperations.html">Bulk.getOperations()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.insert.html">Bulk.insert()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.tojson.html">Bulk.tojson()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Bulk.toString.html">Bulk.toString()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-user-management.html">User Management Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.auth.html">db.auth()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.changeUserPassword.html">db.changeUserPassword()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.createUser.html">db.createUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.dropUser.html">db.dropUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.dropAllUsers.html">db.dropAllUsers()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getUser.html">db.getUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getUsers.html">db.getUsers()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.grantRolesToUser.html">db.grantRolesToUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.removeUser.html">db.removeUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.revokeRolesFromUser.html">db.revokeRolesFromUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.updateUser.html">db.updateUser()</a></li><li class="toctree-l4"><a class="reference internal" href="method/passwordPrompt.html">passwordPrompt()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-role-management.html">Role Management Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.createRole.html">db.createRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.dropRole.html">db.dropRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.dropAllRoles.html">db.dropAllRoles()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getRole.html">db.getRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getRoles.html">db.getRoles()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.grantPrivilegesToRole.html">db.grantPrivilegesToRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.revokePrivilegesFromRole.html">db.revokePrivilegesFromRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.grantRolesToRole.html">db.grantRolesToRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.revokeRolesFromRole.html">db.revokeRolesFromRole()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.updateRole.html">db.updateRole()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-replication.html">Replication Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/rs.add.html">rs.add()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.addArb.html">rs.addArb()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.conf.html">rs.conf()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.freeze.html">rs.freeze()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.help.html">rs.help()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.initiate.html">rs.initiate()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.printReplicationInfo.html">rs.printReplicationInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.printSlaveReplicationInfo.html">rs.printSlaveReplicationInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.reconfig.html">rs.reconfig()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.remove.html">rs.remove()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.slaveOk.html">rs.slaveOk()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.status.html">rs.status()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.stepDown.html">rs.stepDown()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rs.syncFrom.html">rs.syncFrom()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-sharding.html">Sharding Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/sh.addShard.html">sh.addShard()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.addShardTag.html">sh.addShardTag()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.addShardToZone.html">sh.addShardToZone()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.addTagRange.html">sh.addTagRange()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.disableBalancing.html">sh.disableBalancing()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.enableBalancing.html">sh.enableBalancing()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.disableAutoSplit.html">sh.disableAutoSplit</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.enableAutoSplit.html">sh.enableAutoSplit</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.enableSharding.html">sh.enableSharding()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.getBalancerHost.html">sh.getBalancerHost()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.getBalancerState.html">sh.getBalancerState()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.removeTagRange.html">sh.removeTagRange()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.removeRangeFromZone.html">sh.removeRangeFromZone()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.help.html">sh.help()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.isBalancerRunning.html">sh.isBalancerRunning()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.moveChunk.html">sh.moveChunk()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.removeShardTag.html">sh.removeShardTag()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.removeShardFromZone.html">sh.removeShardFromZone()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.setBalancerState.html">sh.setBalancerState()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.shardCollection.html">sh.shardCollection()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.splitAt.html">sh.splitAt()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.splitFind.html">sh.splitFind()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.startBalancer.html">sh.startBalancer()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.status.html">sh.status()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.stopBalancer.html">sh.stopBalancer()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.waitForBalancer.html">sh.waitForBalancer()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.waitForBalancerOff.html">sh.waitForBalancerOff()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.waitForPingChange.html">sh.waitForPingChange()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sh.updateZoneKeyRange.html">sh.updateZoneKeyRange()</a></li><li class="toctree-l4"><a class="reference internal" href="method/convertShardKeyToHashed.html">convertShardKeyToHashed</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-free-monitoring.html">Free Monitoring Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/db.disableFreeMonitoring.html">db.disableFreeMonitoring()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.enableFreeMonitoring.html">db.enableFreeMonitoring()</a></li><li class="toctree-l4"><a class="reference internal" href="method/db.getFreeMonitoringStatus.html">db.getFreeMonitoringStatus</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-constructor.html">Object Constructors and Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/BulkWriteResult.html">BulkWriteResult()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Date.html">Date()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ObjectId.html">ObjectId</a></li><li class="toctree-l4"><a class="reference internal" href="method/ObjectId.getTimestamp.html">ObjectId.getTimestamp()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ObjectId.toString.html">ObjectId.toString()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ObjectId.valueOf.html">ObjectId.valueOf()</a></li><li class="toctree-l4"><a class="reference internal" href="method/UUID.html">UUID()</a></li><li class="toctree-l4"><a class="reference internal" href="method/WriteResult.html">WriteResult()</a></li><li class="toctree-l4"><a class="reference internal" href="method/WriteResult.hasWriteError.html">WriteResult.hasWriteError()</a></li><li class="toctree-l4"><a class="reference internal" href="method/WriteResult.hasWriteConcernError.html">WriteResult.hasWriteConcernError()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-connection.html">Connection Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/connect.html">connect()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.html">Mongo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.getDB.html">Mongo.getDB()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.getReadPrefMode.html">Mongo.getReadPrefMode()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.getReadPrefTagSet.html">Mongo.getReadPrefTagSet()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.isCausalConsistency.html">Mongo.isCausalConsistency()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.setCausalConsistency.html">Mongo.setCausalConsistency()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.setReadPref.html">Mongo.setReadPref()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.setSlaveOk.html">Mongo.setSlaveOk()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.startSession.html">Mongo.startSession()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Mongo.watch.html">Mongo.watch()</a></li><li class="toctree-l4"><a class="reference internal" href="method/Session.html">Session</a><ul><li class="toctree-l5"><a class="reference internal" href="method/Session.abortTransaction.html">Session.abortTransaction()</a></li><li class="toctree-l5"><a class="reference internal" href="method/Session.commitTransaction.html">Session.commitTransaction()</a></li><li class="toctree-l5"><a class="reference internal" href="method/Session.startTransaction.html">Session.startTransaction()</a></li></ul></li><li class="toctree-l4"><a class="reference internal" href="method/SessionOptions.html">SessionOptions</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-native.html">Native Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/cat.html">cat()</a></li><li class="toctree-l4"><a class="reference internal" href="method/cd.html">cd()</a></li><li class="toctree-l4"><a class="reference internal" href="method/copyDbpath.html">copyDbpath()</a></li><li class="toctree-l4"><a class="reference internal" href="method/getHostName.html">getHostName()</a></li><li class="toctree-l4"><a class="reference internal" href="method/getMemInfo.html">getMemInfo()</a></li><li class="toctree-l4"><a class="reference internal" href="method/hostname.html">hostname()</a></li><li class="toctree-l4"><a class="reference internal" href="method/isInteractive.html">isInteractive()</a></li><li class="toctree-l4"><a class="reference internal" href="method/listFiles.html">listFiles()</a></li><li class="toctree-l4"><a class="reference internal" href="method/load.html">load()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ls.html">ls()</a></li><li class="toctree-l4"><a class="reference internal" href="method/md5sumFile.html">md5sumFile()</a></li><li class="toctree-l4"><a class="reference internal" href="method/mkdir.html">mkdir()</a></li><li class="toctree-l4"><a class="reference internal" href="method/pwd.html">pwd()</a></li><li class="toctree-l4"><a class="reference internal" href="method/quit.html">quit()</a></li><li class="toctree-l4"><a class="reference internal" href="method/removeFile.html">removeFile()</a></li><li class="toctree-l4"><a class="reference internal" href="method/resetDbpath.html">resetDbpath()</a></li><li class="toctree-l4"><a class="reference internal" href="method/sleep.html">sleep()</a></li><li class="toctree-l4"><a class="reference internal" href="method/setVerboseShell.html">setVerboseShell()</a></li><li class="toctree-l4"><a class="reference internal" href="method/version.html">version()</a></li><li class="toctree-l4"><a class="reference internal" href="method/isWindows.html">_isWindows()</a></li><li class="toctree-l4"><a class="reference internal" href="method/rand.html">_rand()</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="method/js-client-side-field-level-encryption.html">Client-Side Field Level Encryption Methods</a><ul><li class="toctree-l4"><a class="reference internal" href="method/getKeyVault.html">getKeyVault()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.createKey.html">KeyVault.createKey()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.deleteKey.html">KeyVault.deleteKey()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.getKey.html">KeyVault.getKey()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.getKeys.html">KeyVault.getKeys()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.addKeyAlternateName.html">KeyVault.addKeyAlternateName()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.removeKeyAlternateName.html">KeyVault.removeKeyAlternateName()</a></li><li class="toctree-l4"><a class="reference internal" href="method/KeyVault.getKeyByAltName.html">KeyVault.getKeyByAltName()</a></li><li class="toctree-l4"><a class="reference internal" href="method/getClientEncryption.html">getClientEncryption()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ClientEncryption.encrypt.html">ClientEncryption.encrypt()</a></li><li class="toctree-l4"><a class="reference internal" href="method/ClientEncryption.decrypt.html">ClientEncryption.decrypt()</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="program.html">MongoDB Package Components</a><ul><li class="toctree-l3"><a class="reference internal" href="program/mongod.html"><code class="docutils literal"><span class="pre">mongod</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongos.html"><code class="docutils literal"><span class="pre">mongos</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongo.html"><code class="docutils literal"><span class="pre">mongo</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongod.exe.html"><code class="docutils literal"><span class="pre">mongod.exe</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongos.exe.html"><code class="docutils literal"><span class="pre">mongos.exe</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongodump.html"><code class="docutils literal"><span class="pre">mongodump</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongorestore.html"><code class="docutils literal"><span class="pre">mongorestore</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/bsondump.html"><code class="docutils literal"><span class="pre">bsondump</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongoimport.html"><code class="docutils literal"><span class="pre">mongoimport</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongoexport.html"><code class="docutils literal"><span class="pre">mongoexport</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongostat.html"><code class="docutils literal"><span class="pre">mongostat</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongotop.html"><code class="docutils literal"><span class="pre">mongotop</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongoreplay.html"><code class="docutils literal"><span class="pre">mongoreplay</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongoldap.html"><code class="docutils literal"><span class="pre">mongoldap</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/mongofiles.html"><code class="docutils literal"><span class="pre">mongofiles</span></code></a></li><li class="toctree-l3"><a class="reference internal" href="program/install_compass.html"><code class="docutils literal"><span class="pre">install_compass</span></code></a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="configuration-options.html">Configuration File Options</a><ul><li class="toctree-l3"><a class="reference internal" href="expansion-directives.html">Externally Sourced Configuration File Values</a></li><li class="toctree-l3"><a class="reference internal" href="../tutorial/convert-command-line-options-to-yaml.html">Convert Command-Line Options to YAML</a></li><li class="toctree-l3"><a class="reference internal" href="configuration-file-settings-command-line-options-mapping.html">Configuration File Settings and Command-Line Options Mapping</a></li></ul></li><li class="toctree-l2 current"><a class="reference internal current" href="">MongoDB Server Parameters</a></li><li class="toctree-l2"><a class="reference internal" href="limits.html">MongoDB Limits and Thresholds</a></li><li class="toctree-l2"><a class="reference internal" href="explain-results.html">Explain Results</a></li><li class="toctree-l2"><a class="reference internal" href="system-collections.html">System Collections</a></li><li class="toctree-l2"><a class="reference internal" href="connection-string.html">Connection String URI Format</a></li><li class="toctree-l2"><a class="reference internal" href="collation.html">Collation</a><ul><li class="toctree-l3"><a class="reference internal" href="collation-locales-defaults.html">Collation Locales and Default Parameters</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="mongodb-wire-protocol.html">MongoDB Wire Protocol</a></li><li class="toctree-l2"><a class="reference internal" href="log-messages.html">Log Messages</a></li><li class="toctree-l2"><a class="reference internal" href="exit-codes.html">Exit Codes and Statuses</a></li><li class="toctree-l2"><a class="reference internal" href="glossary.html">Glossary</a></li><li class="toctree-l2"><a class="reference internal" href="default-mongodb-port.html">Default MongoDB Port</a></li><li class="toctree-l2"><a class="reference internal" href="server-sessions.html">Server Sessions</a></li></ul></li><li class="toctree-l1"><a class="reference internal" href="../release-notes.html">Release Notes</a><ul><li class="toctree-l2"><a class="reference internal" href="../release-notes/4.2.html">Release Notes for MongoDB 4.2</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-compatibility.html">Compatibility Changes in MongoDB 4.2</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-upgrade-standalone.html">Upgrade a Standalone to 4.2</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-upgrade-replica-set.html">Upgrade a Replica Set to 4.2</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-upgrade-sharded-cluster.html">Upgrade a Sharded Cluster to 4.2</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-downgrade.html">Downgrade 4.2 to 4.0</a><ul><li class="toctree-l4"><a class="reference internal" href="../release-notes/4.2-downgrade-standalone.html">Downgrade 4.2 Standalone to 4.0</a></li><li class="toctree-l4"><a class="reference internal" href="../release-notes/4.2-downgrade-replica-set.html">Downgrade 4.2 Replica Set to 4.0</a></li><li class="toctree-l4"><a class="reference internal" href="../release-notes/4.2-downgrade-sharded-cluster.html">Downgrade 4.2 Sharded Cluster to 4.0</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.2-changelog.html">4.2 Changelog</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/4.0.html">Release Notes for MongoDB 4.0</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-compatibility.html">Compatibility Changes in MongoDB 4.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-upgrade-standalone.html">Upgrade a Standalone to 4.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-upgrade-replica-set.html">Upgrade a Replica Set to 4.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-upgrade-sharded-cluster.html">Upgrade a Sharded Cluster to 4.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-downgrade-standalone.html">Downgrade 4.0 Standalone to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-downgrade-replica-set.html">Downgrade 4.0 Replica Set to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-downgrade-sharded-cluster.html">Downgrade 4.0 Sharded Cluster to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/4.0-changelog.html">4.0 Changelog</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/3.6.html">Release Notes for MongoDB 3.6</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-changelog.html">3.6 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-compatibility.html">Compatibility Changes in MongoDB 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-upgrade-standalone.html">Upgrade a Standalone to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-upgrade-replica-set.html">Upgrade a Replica Set to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-upgrade-sharded-cluster.html">Upgrade a Sharded Cluster to 3.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-downgrade-standalone.html">Downgrade 3.6 Standalone to 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-downgrade-replica-set.html">Downgrade 3.6 Replica Set to 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.6-downgrade-sharded-cluster.html">Downgrade 3.6 Sharded Cluster to 3.4</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/3.4.html">Release Notes for MongoDB 3.4</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-changelog.html">3.4 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-compatibility.html">Compatibility Changes in MongoDB 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-upgrade-standalone.html">Upgrade a Standalone to 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-upgrade-replica-set.html">Upgrade a Replica Set to 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-upgrade-sharded-cluster.html">Upgrade a Sharded Cluster to 3.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.4-downgrade.html">Downgrade MongoDB 3.4 to 3.2</a><ul><li class="toctree-l4"><a class="reference internal" href="../release-notes/3.4-downgrade-standalone.html">Downgrade 3.4 Standalone to 3.2</a></li><li class="toctree-l4"><a class="reference internal" href="../release-notes/3.4-downgrade-replica-set.html">Downgrade 3.4 Replica Set to 3.2</a></li><li class="toctree-l4"><a class="reference internal" href="../release-notes/3.4-downgrade-sharded-cluster.html">Downgrade 3.4 Sharded Cluster to 3.2</a></li></ul></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/3.2.html">Release Notes for MongoDB 3.2</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.2-changelog.html">3.2 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.2-compatibility.html">Compatibility Changes in MongoDB 3.2</a><ul><li class="toctree-l4"><a class="reference internal" href="../release-notes/3.2-javascript.html">JavaScript Changes in MongoDB 3.2</a></li></ul></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.2-upgrade.html">Upgrade MongoDB to 3.2</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.2-downgrade.html">Downgrade MongoDB from 3.2</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/3.0.html">Release Notes for MongoDB 3.0</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.0-changelog.html">3.0 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.0-compatibility.html">Compatibility Changes in MongoDB 3.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.0-upgrade.html">Upgrade MongoDB to 3.0</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.0-scram.html">Upgrade to SCRAM</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/3.0-downgrade.html">Downgrade MongoDB from 3.0</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/2.6.html">Release Notes for MongoDB 2.6</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.6-changelog.html">2.6 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.6-compatibility.html">Compatibility Changes in MongoDB 2.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.6-upgrade.html">Upgrade MongoDB to 2.6</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.6-upgrade-authorization.html">Upgrade User Authorization Data to 2.6 Format</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.6-downgrade.html">Downgrade MongoDB from 2.6</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/2.4.html">Release Notes for MongoDB 2.4</a><ul><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.4-changelog.html">2.4 Changelog</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.4-javascript.html">JavaScript Changes in MongoDB 2.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.4-upgrade.html">Upgrade MongoDB to 2.4</a></li><li class="toctree-l3"><a class="reference internal" href="../release-notes/2.4-index-types.html">Compatibility and Index Type Changes in MongoDB 2.4</a></li></ul></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/2.2.html">Release Notes for MongoDB 2.2</a></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/2.0.html">Release Notes for MongoDB 2.0</a></li><li class="toctree-l2"><a class="reference internal" href="../release-notes/1.8.html">Release Notes for MongoDB 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            <li>MongoDB Server Parameters</li> 
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                  <div class="section" id="mongodb-server-parameters">
<h1>MongoDB Server Parameters<a class="headerlink" href="#mongodb-server-parameters" title="Permalink to this headline">¶</a></h1>
<div class="contents singlecol local topic" id="on-this-page">
<p class="topic-title first">On this page</p>
<ul class="simple">
<li><a class="reference internal" href="#synopsis" id="id6">Synopsis</a></li>
<li><a class="reference internal" href="#parameters" id="id7">Parameters</a><ul>
<li><a class="reference internal" href="#authentication-parameters" id="id8">Authentication Parameters</a></li>
<li><a class="reference internal" href="#general-parameters" id="id9">General Parameters</a></li>
<li><a class="reference internal" href="#logging-parameters" id="id10">Logging Parameters</a></li>
<li><a class="reference internal" href="#diagnostic-parameters" id="id11">Diagnostic Parameters</a></li>
<li><a class="reference internal" href="#logical-session-parameters" id="id12">Logical Session Parameters</a></li>
<li><a class="reference internal" href="#replication-parameters" id="id13">Replication Parameters</a></li>
<li><a class="reference internal" href="#sharding-parameters" id="id14">Sharding Parameters</a></li>
<li><a class="reference internal" href="#storage-parameters" id="id15">Storage Parameters</a></li>
<li><a class="reference internal" href="#wiredtiger-parameters" id="id16">WiredTiger Parameters</a></li>
<li><a class="reference internal" href="#auditing-parameters" id="id17">Auditing Parameters</a></li>
<li><a class="reference internal" href="#transaction-parameters" id="id18">Transaction Parameters</a></li>
</ul>
</li>
</ul>
</div>
<div class="section" id="synopsis">
<h2>Synopsis<a class="headerlink" href="#synopsis" title="Permalink to this headline">¶</a></h2>
<p>MongoDB provides a number of configuration options that you can set
using:</p>
<ul>
<li><p class="first">the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="o">&lt;</span><span class="nx">parameter</span><span class="o">&gt;:</span> <span class="o">&lt;</span><span class="nx">value</span><span class="o">&gt;</span>  <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</li>
<li><p class="first">the <a class="reference internal" href="privilege-actions.html#setParameter" title="setParameter"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">setParameter</span></code></a> configuration setting:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-yaml"><div class="highlight"><pre><span></span><span class="nt">setParameter</span><span class="p">:</span>
   <span class="nt">&lt;parameter1&gt;</span><span class="p">:</span> <span class="l l-Scalar l-Scalar-Plain">&lt;value1&gt;</span>
   <span class="l l-Scalar l-Scalar-Plain">...</span>
</pre></div>
</div>
</div>
</li>
<li><p class="first">the <code class="docutils literal"><span class="pre">--setParameter</span></code> command-line option for <a class="reference internal" href="program/mongod.html#cmdoption-mongod-setparameter"><code class="xref std std-option docutils literal"><span class="pre">mongod</span></code></a>
and <a class="reference internal" href="program/mongos.html#cmdoption-mongos-setparameter"><code class="xref std std-option docutils literal"><span class="pre">mongos</span></code></a>:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter &lt;parameter&gt;<span class="o">=</span>&lt;value&gt;
mongos --setParameter &lt;parameter&gt;<span class="o">=</span>&lt;value&gt;
</pre></div>
</div>
</div>
</li>
</ul>
<p>For additional configuration options, see
<a class="reference internal" href="configuration-options.html"><span class="doc">Configuration File Options</span></a>, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
</div>
<div class="section" id="parameters">
<h2>Parameters<a class="headerlink" href="#parameters" title="Permalink to this headline">¶</a></h2>
<div class="section" id="authentication-parameters">
<h3>Authentication Parameters<a class="headerlink" href="#authentication-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.authenticationMechanisms">
<code class="descname">authenticationMechanisms</code><a class="headerlink" href="#param.authenticationMechanisms" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionchanged">
<p><span class="versionmodified">Changed in version 4.0: </span>Remove support for the deprecated <code class="docutils literal"><span class="pre">MONGODB-CR</span></code> authentication mechanism.</p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Specifies the list of authentication mechanisms the server accepts. Set
this to one or more of the following values. If you specify multiple
values, use a comma-separated list and no spaces. For descriptions
of the authentication mechanisms, see <a class="reference internal" href="../core/authentication.html"><span class="doc">Authentication</span></a>.</p>
<table border="1" class="colwidths-given docutils">
<colgroup>
<col width="33%" />
<col width="67%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Value</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><a class="reference internal" href="../core/security-scram.html#authentication-scram-sha-1"><span class="std std-ref">SCRAM-SHA-1</span></a></td>
<td><a class="reference external" href="https://tools.ietf.org/html/rfc5802">RFC 5802</a> standard
Salted Challenge Response Authentication Mechanism using the SHA-1
hash function.</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="../core/security-scram.html#authentication-scram-sha-256"><span class="std std-ref">SCRAM-SHA-256</span></a></td>
<td><p class="first"><a class="reference external" href="https://tools.ietf.org/html/rfc7677">RFC 7677</a> standard
Salted Challenge Response Authentication Mechanism using the SHA-256
hash function.</p>
<p>Requires featureCompatibilityVersion set to <code class="docutils literal"><span class="pre">4.0</span></code>.</p>
<div class="last versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="../core/security-x.509.html#security-auth-x509"><span class="std std-ref">MONGODB-X509</span></a></td>
<td>MongoDB TLS/SSL certificate authentication.</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="../core/authentication-mechanisms-enterprise.html#security-auth-kerberos"><span class="std std-ref">GSSAPI</span></a> (Kerberos)</td>
<td>External authentication using Kerberos. This mechanism is
available only in <a class="reference external" href="http://www.mongodb.com/products/mongodb-enterprise-advanced?jmp=docs">MongoDB Enterprise</a>.</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="../core/authentication-mechanisms-enterprise.html#security-auth-ldap"><span class="std std-ref">PLAIN</span></a> (LDAP SASL)</td>
<td>External authentication using LDAP. You can also use <code class="docutils literal"><span class="pre">PLAIN</span></code>
for authenticating in-database users. <code class="docutils literal"><span class="pre">PLAIN</span></code> transmits
passwords in plain text. This mechanism is available only in
<a class="reference external" href="http://www.mongodb.com/products/mongodb-enterprise-advanced?jmp=docs">MongoDB Enterprise</a>.</td>
</tr>
</tbody>
</table>
<p>You can only set <a class="reference internal" href="#param.authenticationMechanisms" title="authenticationMechanisms"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">authenticationMechanisms</span></code></a> during
start-up.</p>
<p>For example, to specify both <code class="docutils literal"><span class="pre">PLAIN</span></code> and <code class="docutils literal"><span class="pre">SCRAM-SHA-256</span></code> as the
authentication mechanisms, use the following command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">authenticationMechanisms</span><span class="o">=</span>PLAIN,SCRAM-SHA-256 --auth
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.clusterAuthMode">
<code class="descname">clusterAuthMode</code><a class="headerlink" href="#param.clusterAuthMode" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Set the <a class="reference internal" href="configuration-options.html#security.clusterAuthMode" title="security.clusterAuthMode"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">clusterAuthMode</span></code></a> to either <code class="docutils literal"><span class="pre">sendX509</span></code> or
<code class="docutils literal"><span class="pre">x509</span></code>. Useful during <a class="reference internal" href="../tutorial/upgrade-keyfile-to-x509.html#upgrade-to-x509-internal-authentication"><span class="std std-ref">rolling upgrade to use x509 for
membership authentication</span></a>
to minimize downtime.</p>
<p>For more information about TLS/SSL and MongoDB, see
<a class="reference internal" href="../tutorial/configure-ssl.html"><span class="doc">Configure mongod and mongos for TLS/SSL</span></a> and
<a class="reference internal" href="../tutorial/configure-ssl-clients.html"><span class="doc">TLS/SSL Configuration for Clients</span></a> .</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, clusterAuthMode: <span class="s2">&quot;sendX509&quot;</span> <span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.enableLocalhostAuthBypass">
<code class="descname">enableLocalhostAuthBypass</code><a class="headerlink" href="#param.enableLocalhostAuthBypass" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Specify <code class="docutils literal"><span class="pre">0</span></code> or <code class="docutils literal"><span class="pre">false</span></code> to disable localhost authentication
bypass. Enabled by default.</p>
<p><a class="reference internal" href="#param.enableLocalhostAuthBypass" title="enableLocalhostAuthBypass"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">enableLocalhostAuthBypass</span></code></a> is not available using
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command. Use the
<a class="reference internal" href="privilege-actions.html#setParameter" title="setParameter"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">setParameter</span></code></a> option in the configuration file or the
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-setparameter"><code class="xref std std-option docutils literal"><span class="pre">--setParameter</span></code></a> option on the
command line.</p>
<p>See <a class="reference internal" href="../core/security-users.html#localhost-exception"><span class="std std-ref">Localhost Exception</span></a> for more information.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.KeysRotationIntervalSec">
<code class="descname">KeysRotationIntervalSec</code><a class="headerlink" href="#param.KeysRotationIntervalSec" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p><em>Default</em>: 7776000 seconds (90 days)</p>
<p>Specifies the number of seconds for which an <a class="reference external" href="https://en.wikipedia.org/wiki/Hash-based_message_authentication_code">HMAC signing key</a>
is valid before rotating to the next one. This parameter is intended
primarily to facilitate authentication testing.</p>
<p>You can only set <a class="reference internal" href="#param.KeysRotationIntervalSec" title="KeysRotationIntervalSec"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">KeysRotationIntervalSec</span></code></a> during
start-up, and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapUserCacheInvalidationInterval">
<code class="descname">ldapUserCacheInvalidationInterval</code><a class="headerlink" href="#param.ldapUserCacheInvalidationInterval" title="Permalink to this definition">¶</a></dt>
<dd><p>For use with MongoDB deployments using
<a class="reference internal" href="../core/security-ldap-external.html#security-ldap-external"><span class="std std-ref">LDAP Authorization</span></a>. Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>
instances only.</p>
<p>The interval (in seconds) that the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance
waits between external user cache flushes. After MongoDB flushes the
external user cache, MongoDB
reacquires authorization data from the LDAP server the
next time an LDAP-authorized user issues an operation.</p>
<p>Increasing the value specified increases the amount of time
MongoDB and the LDAP server can be out of sync, but reduces the load on
the LDAP server. Conversely, decreasing the value specified
decreases the time MongoDB and the LDAP server can be out of sync while
increasing the load on the LDAP server.</p>
<p>Defaults to 30 seconds.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapUseConnectionPool">
<code class="descname">ldapUseConnectionPool</code><a class="headerlink" href="#param.ldapUseConnectionPool" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.9.</span></p>
</div>
<p>Specifies whether MongoDB should use connection pooling when
connecting to the LDAP server for authentication/authorization.</p>
<p><strong>Starting in version 4.2</strong>, MongoDB uses the following default values:</p>
<ul class="simple">
<li>true on Windows.</li>
<li>true on Linux where MongoDB Enterprise binaries are linked against
<code class="docutils literal"><span class="pre">libldap_r</span></code>.</li>
<li>false on Linux where MongoDB Enterprise binaries are linked against
<code class="docutils literal"><span class="pre">libldap</span></code>.</li>
</ul>
<p><strong>In earlier versions (versions 4.0.9+)</strong>, the default value is
<code class="docutils literal"><span class="pre">false</span></code>.</p>
<p>You can only set <a class="reference internal" href="#param.ldapUseConnectionPool" title="ldapUseConnectionPool"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapUseConnectionPool</span></code></a> during
start-up, and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolUseLatencyForHostPriority">
<code class="descname">ldapConnectionPoolUseLatencyForHostPriority</code><a class="headerlink" href="#param.ldapConnectionPoolUseLatencyForHostPriority" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p><em>Default</em>: true</p>
<p>A boolean that determines whether the LDAP connection pool (see
<a class="reference internal" href="#param.ldapUseConnectionPool" title="ldapUseConnectionPool"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapUseConnectionPool</span></code></a>) should use latency of the LDAP
servers to determine the connection order (from lowest latency to
highest).</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolUseLatencyForHostPriority" title="ldapConnectionPoolUseLatencyForHostPriority"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolUseLatencyForHostPriority</span></code></a> during
start-up, and cannot change this setting during runtime with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolMinimumConnectionsPerHost">
<code class="descname">ldapConnectionPoolMinimumConnectionsPerHost</code><a class="headerlink" href="#param.ldapConnectionPoolMinimumConnectionsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p><em>Default</em>: 1</p>
<p>The minimum number of connections to keep open to each LDAP server.</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolMinimumConnectionsPerHost" title="ldapConnectionPoolMinimumConnectionsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolMinimumConnectionsPerHost</span></code></a> during
start-up, and cannot change this setting during runtime with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolMaximumConnectionsPerHost">
<code class="descname">ldapConnectionPoolMaximumConnectionsPerHost</code><a class="headerlink" href="#param.ldapConnectionPoolMaximumConnectionsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p>The maximum number of connections to keep open to each LDAP server.</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolMaximumConnectionsPerHost" title="ldapConnectionPoolMaximumConnectionsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolMaximumConnectionsPerHost</span></code></a> during
start-up, and cannot change this setting during runtime with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolMaximumConnectionsInProgressPerHost">
<code class="descname">ldapConnectionPoolMaximumConnectionsInProgressPerHost</code><a class="headerlink" href="#param.ldapConnectionPoolMaximumConnectionsInProgressPerHost" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p>The maximum number of in-progress connect operations to each LDAP server.</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolMaximumConnectionsInProgressPerHost" title="ldapConnectionPoolMaximumConnectionsInProgressPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolMaximumConnectionsInProgressPerHost</span></code></a>
during start-up, and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolHostRefreshIntervalMillis">
<code class="descname">ldapConnectionPoolHostRefreshIntervalMillis</code><a class="headerlink" href="#param.ldapConnectionPoolHostRefreshIntervalMillis" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p><em>Default</em>: 60000</p>
<p>The number of milliseconds in-between health checks of the pooled
LDAP connections.</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolHostRefreshIntervalMillis" title="ldapConnectionPoolHostRefreshIntervalMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolHostRefreshIntervalMillis</span></code></a> during
start-up, and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ldapConnectionPoolIdleHostTimeoutSecs">
<code class="descname">ldapConnectionPoolIdleHostTimeoutSecs</code><a class="headerlink" href="#param.ldapConnectionPoolIdleHostTimeoutSecs" title="Permalink to this definition">¶</a></dt>
<dd><p><em>New in version 4.2.1 and 4.0.13</em></p>
<p><em>Default</em>: 300</p>
<p>The maximum number of seconds that the pooled connections to an LDAP
server can remain idle before being closed.</p>
<p>You can only set
<a class="reference internal" href="#param.ldapConnectionPoolIdleHostTimeoutSecs" title="ldapConnectionPoolIdleHostTimeoutSecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ldapConnectionPoolIdleHostTimeoutSecs</span></code></a> during
start-up, and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.opensslCipherConfig">
<code class="descname">opensslCipherConfig</code><a class="headerlink" href="#param.opensslCipherConfig" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 4.0: </span>With the use of native TLS/SSL libraries, the parameter
<a class="reference internal" href="#param.opensslCipherConfig" title="opensslCipherConfig"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">opensslCipherConfig</span></code></a> is supported for Linux/BSD and
no longer supported in Windows and macOS. See <a class="reference internal" href="../release-notes/4.0.html#tls"><span class="std std-ref">MongoDB 4.0
TLS/SSL</span></a>.</p>
</div>
<p>Specify the cipher string for OpenSSL when using TLS/SSL encryption.
For a list of cipher strings, see
<a class="reference external" href="https://www.openssl.org/docs/man1.0.2/apps/ciphers.html#CIPHER-STRINGS">https://www.openssl.org/docs/man1.0.2/apps/ciphers.html#CIPHER-STRINGS</a></p>
<p>You can only set <a class="reference internal" href="#param.opensslCipherConfig" title="opensslCipherConfig"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">opensslCipherConfig</span></code></a> during start-up, and
cannot change this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
database command.</p>
<p>For version 4.2 and greater, the use of <code class="docutils literal"><span class="pre">TLS</span></code> options is preferred
over <code class="docutils literal"><span class="pre">SSL</span></code> options. The TLS options have the same functionality as
the <code class="docutils literal"><span class="pre">SSL</span></code> options.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">opensslCipherConfig</span><span class="o">=</span><span class="s1">&#39;HIGH:!EXPORT:!aNULL@STRENGTH&#39;</span> --tlsMode requireTLS --tlsCertificateKeyFile Certs/server.pem
</pre></div>
</div>
</div>
<p>For versions 4.0 and earlier:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">opensslCipherConfig</span><span class="o">=</span><span class="s1">&#39;HIGH:!EXPORT:!aNULL@STRENGTH&#39;</span> --sslMode requireSSL --sslPEMKeyFile Certs/server.pem
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.opensslDiffieHellmanParameters">
<code class="descname">opensslDiffieHellmanParameters</code><a class="headerlink" href="#param.opensslDiffieHellmanParameters" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p><em>Available on Linux only</em></p>
<p>Specify the path to the PEM file that contains the OpenSSL
Diffie-Hellman parameters. Specifying the OpenSSL Diffie-Hellman
parameters enables support for <a class="reference internal" href="../core/security-transport-encryption.html#dhe"><span class="std std-ref">Ephemeral Diffie-Hellman (DHE)</span></a> cipher suites during
TLS/SSL encryption.</p>
<p>Ephemeral Diffie-Hellman (DHE) cipher suites (and Ephemeral Elliptic
Curve Diffie-Hellman (ECDHE) cipher suites) provide
<a class="reference internal" href="../core/security-transport-encryption.html#tls-forward-secrecy"><span class="std std-ref">Forward Secrecy</span></a>. <a class="reference internal" href="../core/security-transport-encryption.html#tls-forward-secrecy"><span class="std std-ref">Forward Secrecy</span></a> cipher suites
create an ephemeral session key that is protected by the server’s
private key but never transmitted. This ensures that even if a
server’s private key is compromised, you cannot decrypt past
sessions with the compromised key.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Starting in MongoDB 4.2, if
<a class="reference internal" href="#param.opensslDiffieHellmanParameters" title="opensslDiffieHellmanParameters"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">opensslDiffieHellmanParameters</span></code></a> is unset but
<a class="reference internal" href="../core/security-transport-encryption.html#ecdhe"><span class="std std-ref">ECDHE is enabled</span></a>, MongoDB enables DHE using
<code class="docutils literal"><span class="pre">ffdhe3072</span></code> Diffie-Hellman parameter, as defined in
<span class="target" id="index-0"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc7919.html#appendix-A.2"><strong>RFC 7919#appendix-A.2</strong></a>. The <code class="docutils literal"><span class="pre">ffdhe3072</span></code> is a strong parameter
(i.e. size is greater than 1024). Strong parameters are not
supported with Java 6 and 7 unless extended support has been
purchased from Oracle.</p>
</div>
<p>You can only set <a class="reference internal" href="#param.opensslDiffieHellmanParameters" title="opensslDiffieHellmanParameters"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">opensslDiffieHellmanParameters</span></code></a> during
startup, and cannot change this setting using the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<p>If for performance reasons, you need to disable support for DHE
cipher suites, use the <a class="reference internal" href="#param.opensslCipherConfig" title="opensslCipherConfig"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">opensslCipherConfig</span></code></a> parameter:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">opensslCipherConfig</span><span class="o">=</span><span class="s1">&#39;HIGH:!EXPORT:!aNULL:!DHE:!kDHE@STRENGTH&#39;</span> ...
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.saslauthdPath">
<code class="descname">saslauthdPath</code><a class="headerlink" href="#param.saslauthdPath" title="Permalink to this definition">¶</a></dt>
<dd><div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Available only in MongoDB Enterprise (except MongoDB Enterprise for Windows).</p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Specify the path to the Unix Domain Socket of the <code class="docutils literal"><span class="pre">saslauthd</span></code>
instance to use for proxy authentication.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.saslHostName">
<code class="descname">saslHostName</code><a class="headerlink" href="#param.saslHostName" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><a class="reference internal" href="#param.saslHostName" title="saslHostName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslHostName</span></code></a> overrides MongoDB’s default hostname
detection for the purpose of configuring SASL and Kerberos
authentication.</p>
<p><a class="reference internal" href="#param.saslHostName" title="saslHostName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslHostName</span></code></a> does not affect the hostname of the
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance for any purpose
beyond the configuration of SASL and Kerberos.</p>
<p>You can only set <a class="reference internal" href="#param.saslHostName" title="saslHostName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslHostName</span></code></a> during start-up, and
cannot change this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
database command.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p><a class="reference internal" href="#param.saslHostName" title="saslHostName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslHostName</span></code></a> supports Kerberos authentication and is
only included in MongoDB Enterprise. For more information, see the
following:</p>
<ul class="last simple">
<li>Linux:
<a class="reference internal" href="../tutorial/control-access-to-mongodb-with-kerberos-authentication.html"><span class="doc">Configure MongoDB with Kerberos Authentication on Linux</span></a></li>
<li>Windows:
<a class="reference internal" href="../tutorial/control-access-to-mongodb-windows-with-kerberos-authentication.html"><span class="doc">Configure MongoDB with Kerberos Authentication on Windows</span></a></li>
</ul>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.saslServiceName">
<code class="descname">saslServiceName</code><a class="headerlink" href="#param.saslServiceName" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Allows users to override the default <a class="reference internal" href="../tutorial/control-access-to-mongodb-with-kerberos-authentication.html"><span class="doc">Kerberos</span></a>
service name component of the <a class="reference internal" href="../tutorial/control-access-to-mongodb-with-kerberos-authentication.html"><span class="doc">Kerberos</span></a>
principal name, on a per-instance basis. If unspecified, the
default value is <code class="docutils literal"><span class="pre">mongodb</span></code>.</p>
<p>MongoDB only permits setting <a class="reference internal" href="#param.saslServiceName" title="saslServiceName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslServiceName</span></code></a> at
startup. The <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command can not change
this setting.</p>
<p><a class="reference internal" href="#param.saslServiceName" title="saslServiceName"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">saslServiceName</span></code></a> is only available in MongoDB
Enterprise.</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">Ensure that your driver supports alternate service names.</p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.scramIterationCount">
<code class="descname">scramIterationCount</code><a class="headerlink" href="#param.scramIterationCount" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: <code class="docutils literal"><span class="pre">10000</span></code></p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Changes the number of hashing iterations used for all new
<code class="docutils literal"><span class="pre">SCRAM-SHA-1</span></code> passwords. More iterations increase the amount of
time required for clients to authenticate to MongoDB, but makes
passwords less susceptible to brute-force attempts. The default
value is ideal for most common use cases and requirements.</p>
<p>If you modify this value, it does not change the iteration count for
existing passwords. The <a class="reference internal" href="#param.scramIterationCount" title="scramIterationCount"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">scramIterationCount</span></code></a> value must
be <code class="docutils literal"><span class="pre">5000</span></code> or greater.</p>
<p>For example, the following sets the <a class="reference internal" href="#param.scramIterationCount" title="scramIterationCount"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">scramIterationCount</span></code></a>
to <code class="docutils literal"><span class="pre">12000</span></code>.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">scramIterationCount</span><span class="o">=</span><span class="m">12000</span>
</pre></div>
</div>
</div>
<p>Or, if using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command within the
<a class="reference internal" href="program/mongo.html#bin.mongo" title="bin.mongo"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongo</span></code></a> shell:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">scramIterationCount</span><span class="o">:</span> <span class="mi">12000</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<ul class="last simple">
<li><a class="reference internal" href="method/db.changeUserPassword.html#db.changeUserPassword" title="db.changeUserPassword()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.changeUserPassword()</span></code></a></li>
<li><a class="reference internal" href="method/db.createUser.html#db.createUser" title="db.createUser()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.createUser()</span></code></a></li>
<li><a class="reference internal" href="method/db.updateUser.html#db.updateUser" title="db.updateUser()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.updateUser()</span></code></a></li>
</ul>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.scramSHA256IterationCount">
<code class="descname">scramSHA256IterationCount</code><a class="headerlink" href="#param.scramSHA256IterationCount" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
<p><em>Default</em>: <code class="docutils literal"><span class="pre">15000</span></code></p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Changes the number of hashing iterations used for all new
<code class="docutils literal"><span class="pre">SCRAM-SHA-256</span></code> passwords. More iterations increase the amount of
time required for clients to authenticate to MongoDB, but makes
passwords less susceptible to brute-force attempts. The default
value is ideal for most common use cases and requirements.</p>
<p>If you modify this value, it does not change iteration count for
existing passwords. The <a class="reference internal" href="#param.scramSHA256IterationCount" title="scramSHA256IterationCount"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">scramSHA256IterationCount</span></code></a> value
must be <code class="docutils literal"><span class="pre">5000</span></code> or greater.</p>
<p>For example, the following sets the <a class="reference internal" href="#param.scramSHA256IterationCount" title="scramSHA256IterationCount"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">scramSHA256IterationCount</span></code></a>
to <code class="docutils literal"><span class="pre">20000</span></code>.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">scramSHA256IterationCount</span><span class="o">=</span><span class="m">20000</span>
</pre></div>
</div>
</div>
<p>Or, if using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command within the
<a class="reference internal" href="program/mongo.html#bin.mongo" title="bin.mongo"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongo</span></code></a> shell:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">scramSHA256IterationCount</span><span class="o">:</span> <span class="mi">20000</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<ul class="last simple">
<li><a class="reference internal" href="method/db.changeUserPassword.html#db.changeUserPassword" title="db.changeUserPassword()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.changeUserPassword()</span></code></a></li>
<li><a class="reference internal" href="method/db.createUser.html#db.createUser" title="db.createUser()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.createUser()</span></code></a></li>
<li><a class="reference internal" href="method/db.updateUser.html#db.updateUser" title="db.updateUser()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.updateUser()</span></code></a></li>
</ul>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.sslMode">
<code class="descname">sslMode</code><a class="headerlink" href="#param.sslMode" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Set the <a class="reference internal" href="configuration-options.html#net.ssl.mode" title="net.ssl.mode"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.ssl.mode</span></code></a> to either <code class="docutils literal"><span class="pre">preferSSL</span></code> or
<code class="docutils literal"><span class="pre">requireSSL</span></code>. Useful during <a class="reference internal" href="../tutorial/upgrade-cluster-to-ssl.html"><span class="doc">rolling upgrade to TLS/SSL</span></a> to minimize downtime.</p>
<p>For more information about TLS/SSL and MongoDB, see
<a class="reference internal" href="../tutorial/configure-ssl.html"><span class="doc">Configure mongod and mongos for TLS/SSL</span></a> and
<a class="reference internal" href="../tutorial/configure-ssl-clients.html"><span class="doc">TLS/SSL Configuration for Clients</span></a> .</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, sslMode: <span class="s2">&quot;preferSSL&quot;</span> <span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.tlsMode" title="tlsMode"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tlsMode</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.tlsMode">
<code class="descname">tlsMode</code><a class="headerlink" href="#param.tlsMode" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Set to either:</p>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">preferTLS</span></code></li>
<li><code class="docutils literal"><span class="pre">requireTLS</span></code></li>
</ul>
<p>The <a class="reference internal" href="#param.tlsMode" title="tlsMode"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tlsMode</span></code></a> parameter is useful during <a class="reference internal" href="../tutorial/upgrade-cluster-to-ssl.html"><span class="doc">rolling
upgrade to TLS/SSL</span></a> to minimize
downtime.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, tlsMode: <span class="s2">&quot;preferTLS&quot;</span> <span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
<p>For more information about TLS/SSL and MongoDB, see
<a class="reference internal" href="../tutorial/configure-ssl.html"><span class="doc">Configure mongod and mongos for TLS/SSL</span></a> and
<a class="reference internal" href="../tutorial/configure-ssl-clients.html"><span class="doc">TLS/SSL Configuration for Clients</span></a> .</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.sslMode" title="sslMode"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">sslMode</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.tlsWithholdClientCertificate">
<code class="descname">tlsWithholdClientCertificate</code><a class="headerlink" href="#param.tlsWithholdClientCertificate" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: false</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>A TLS certificate is set for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> either by the
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsclusterfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsClusterFile</span></code></a> option or by the
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlscertificatekeyfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsCertificateKeyFile</span></code></a> option when
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsclusterfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsClusterFile</span></code></a> is not set. If the TLS
certificate is set, by default, the instance sends the certificate when
initiating intra-cluster communications with other
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instances in
the deployment. Set <code class="docutils literal"><span class="pre">tlsWithholdClientCertificate</span></code> to <code class="docutils literal"><span class="pre">1</span></code> or <code class="docutils literal"><span class="pre">true</span></code> to
direct the instance to withhold sending its TLS certificate during these
communications. Use this option with
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsallowconnectionswithoutcertificates"><code class="xref std std-option docutils literal"><span class="pre">--tlsAllowConnectionsWithoutCertificates</span></code></a>
(to allow inbound connections without certificates) on all members of the
deployment. <code class="docutils literal"><span class="pre">tlsWithholdClientCertificate</span></code> is mutually exclusive with
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-clusterauthmode"><code class="xref std std-option docutils literal"><span class="pre">--clusterAuthMode</span> <span class="pre">x509</span></code></a>.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.tlsX509ClusterAuthDNOverride">
<code class="descname">tlsX509ClusterAuthDNOverride</code><a class="headerlink" href="#param.tlsX509ClusterAuthDNOverride" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>An alternative Distinguished Name (DN) that the instance can also
use to identify members of the deployment.</p>
<p>For a MongoDB deployment that uses x.509 certificates for
<a class="reference internal" href="configuration-options.html#security.clusterAuthMode" title="security.clusterAuthMode"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">clusterAuthMode</span></code></a>, deployment members identify
each other using x.509 certificates (
<a class="reference internal" href="configuration-options.html#net.tls.clusterFile" title="net.tls.clusterFile"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.tls.clusterFile</span></code></a>, if specified, and
<a class="reference internal" href="configuration-options.html#net.tls.certificateKeyFile" title="net.tls.certificateKeyFile"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.tls.certificateKeyFile</span></code></a>) during intra-cluster
communications. For members of the same deployment, the <code class="docutils literal"><span class="pre">DN</span></code> from
their certificates must have the same Organization attributes
(<code class="docutils literal"><span class="pre">O</span></code>’s), the Organizational Unit attributes (<code class="docutils literal"><span class="pre">OU</span></code>’s), and the
Domain Components (<code class="docutils literal"><span class="pre">DC</span></code>’s).</p>
<p>If <a class="reference internal" href="#param.tlsX509ClusterAuthDNOverride" title="tlsX509ClusterAuthDNOverride"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tlsX509ClusterAuthDNOverride</span></code></a> is set for a member,
the member can also use the override value when comparing the <code class="docutils literal"><span class="pre">DN</span></code>
components (<code class="docutils literal"><span class="pre">O</span></code>’s, <code class="docutils literal"><span class="pre">OU</span></code>’s, and <code class="docutils literal"><span class="pre">DC</span></code>’s) of the presented
certificates. That is the member checks the presented certificates
against its
<a class="reference internal" href="configuration-options.html#net.tls.clusterFile" title="net.tls.clusterFile"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.tls.clusterFile</span></code></a>/<a class="reference internal" href="configuration-options.html#net.tls.certificateKeyFile" title="net.tls.certificateKeyFile"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.tls.certificateKeyFile</span></code></a>.
If the DN does not match, the member checks the presented
certifcate against the <a class="reference internal" href="#param.tlsX509ClusterAuthDNOverride" title="tlsX509ClusterAuthDNOverride"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tlsX509ClusterAuthDNOverride</span></code></a>
value.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">If set, you must set this parameter on all members of the
deployment.</p>
</div>
<p>You can use this parameter for a rolling update of certificates to
new certificates that contain a new <code class="docutils literal"><span class="pre">DN</span></code> value. See
<a class="reference internal" href="../tutorial/rotate-x509-membership-certificates.html"><span class="doc">Rolling Update of x.509 Cluster Certificates that Contain New DN</span></a>.</p>
<p>For more information about membership certificate requirements, see
<a class="reference internal" href="../core/security-x.509.html#x509-member-certificate-requirements"><span class="std std-ref">Member Certificate Requirements</span></a> for details.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.sslWithholdClientCertificate">
<code class="descname">sslWithholdClientCertificate</code><a class="headerlink" href="#param.sslWithholdClientCertificate" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: false</p>
<div class="deprecated">
<p><span class="versionmodified">Deprecated since version 4.2: </span>Use <a class="reference internal" href="#param.tlsWithholdClientCertificate" title="tlsWithholdClientCertificate"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tlsWithholdClientCertificate</span></code></a> instead.</p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>A TLS certificate is set for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> either by the
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsclusterfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsClusterFile</span></code></a> option or by the
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlscertificatekeyfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsCertificateKeyFile</span></code></a> option when
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsclusterfile"><code class="xref std std-option docutils literal"><span class="pre">--tlsClusterFile</span></code></a> is not set. If the TLS
certificate is set, by default, the instance sends the certificate when
initiating intra-cluster communications with other
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instances in
the deployment. Set <code class="docutils literal"><span class="pre">sslWithholdClientCertificate</span></code> to <code class="docutils literal"><span class="pre">1</span></code> or <code class="docutils literal"><span class="pre">true</span></code> to
direct the instance to withhold sending its TLS certificate during these
communications. Use this option with
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-tlsallowconnectionswithoutcertificates"><code class="xref std std-option docutils literal"><span class="pre">--tlsAllowConnectionsWithoutCertificates</span></code></a>
(to allow inbound connections without certificates) on all members of the
deployment. <code class="docutils literal"><span class="pre">sslWithholdClientCertificate</span></code> is mutually exclusive with
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-clusterauthmode"><code class="xref std std-option docutils literal"><span class="pre">--clusterAuthMode</span> <span class="pre">x509</span></code></a>.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.userCacheInvalidationIntervalSecs">
<code class="descname">userCacheInvalidationIntervalSecs</code><a class="headerlink" href="#param.userCacheInvalidationIntervalSecs" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 30</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>On a <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance, specifies the interval (in seconds)
at which the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance checks to determine whether
the in-memory cache of <a class="reference internal" href="system-users-collection.html"><span class="doc">user objects</span></a> has stale data, and if so,
clears the cache. If there are no changes to user objects,
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> will not clear the cache.</p>
<p>This parameter has a minimum value of <code class="docutils literal"><span class="pre">1</span></code> second and a maximum
value of <code class="docutils literal"><span class="pre">86400</span></code> seconds (24 hours).</p>
</dd></dl>

<dl class="parameter">
<dt id="param.authFailedDelayMs">
<code class="descname">authFailedDelayMs</code><a class="headerlink" href="#param.authFailedDelayMs" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 0</p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
<div class="admonition-enterprise-feature admonition">
<p class="first admonition-title">Enterprise Feature</p>
<p class="last">Available in MongoDB Enterprise only.</p>
</div>
<p>The number of milliseconds to wait before informing clients that their
authentication attempt has failed. This parameter may be in the range
<code class="docutils literal"><span class="pre">0</span></code> to <code class="docutils literal"><span class="pre">5000</span></code>, inclusive.</p>
<p>Setting this parameter makes brute-force login attacks on a database
more time-consuming. However, clients waiting for a response from the
MongoDB server still consume server resources, and this may adversely
impact benign login attempts if the server is denying access to many
other clients simultaneously.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.allowRolesFromX509Certificates">
<code class="descname">allowRolesFromX509Certificates</code><a class="headerlink" href="#param.allowRolesFromX509Certificates" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: true</p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Available starting in MongoDB 4.0.11 (and 3.6.14 and 3.4.22)</em></p>
<p>A boolean flag that allows or disallows the retrieval of
authorization roles from client x.509 certificates.</p>
<p>You can only set <a class="reference internal" href="#param.allowRolesFromX509Certificates" title="allowRolesFromX509Certificates"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">allowRolesFromX509Certificates</span></code></a> during
startup in the config file or on the command line.</p>
</dd></dl>

</div>
<div class="section" id="general-parameters">
<h3>General Parameters<a class="headerlink" href="#general-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.connPoolMaxShardedConnsPerHost">
<code class="descname">connPoolMaxShardedConnsPerHost</code><a class="headerlink" href="#param.connPoolMaxShardedConnsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 200</p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the maximum size of the legacy connection pools for communication to the
shards. The size of a pool does not prevent the creation of
additional connections, but <em>does</em> prevent the connection pools from
retaining connections above this limit.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The parameter is separate from the connections in TaskExecutor
pools. See <a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxSize" title="ShardingTaskExecutorPoolMaxSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxSize</span></code></a>.</p>
</div>
<p>Increase the <a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a> value
<strong>only</strong> if the number of connections in a connection pool has a
high level of churn or if the total number of created connections
increase.</p>
<p>You can only set <a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a> during
startup in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">connPoolMaxShardedConnsPerHost</span><span class="o">=</span><span class="m">250</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.connPoolMaxShardedInUseConnsPerHost">
<code class="descname">connPoolMaxShardedInUseConnsPerHost</code><a class="headerlink" href="#param.connPoolMaxShardedInUseConnsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.3.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the maximum number of in-use connections at any given time for
the legacy sharded cluster connection pools.</p>
<p>By default, the parameter is unset.</p>
<p>You can only set <a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a> during
startup in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">connPoolMaxShardedInUseConnsPerHost</span><span class="o">=</span><span class="m">100</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.shardedConnPoolIdleTimeoutMinutes">
<code class="descname">shardedConnPoolIdleTimeoutMinutes</code><a class="headerlink" href="#param.shardedConnPoolIdleTimeoutMinutes" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.3.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the time limit that a connection in the legacy sharded cluster
connection pool can remain idle before being closed.</p>
<p>By default, the parameter is unset.</p>
<p>You can only set <a class="reference internal" href="#param.shardedConnPoolIdleTimeoutMinutes" title="shardedConnPoolIdleTimeoutMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">shardedConnPoolIdleTimeoutMinutes</span></code></a> during
startup in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">shardedConnPoolIdleTimeoutMinutes</span><span class="o">=</span><span class="m">10</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.connPoolMaxConnsPerHost">
<code class="descname">connPoolMaxConnsPerHost</code><a class="headerlink" href="#param.connPoolMaxConnsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 200</p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the maximum size of the legacy connection pools for outgoing connections
to other <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instances in the global connection pool. The size
of a pool does not prevent the creation of additional connections,
but <em>does</em> prevent a connection pool from retaining connections in
excess of the value of <a class="reference internal" href="#param.connPoolMaxConnsPerHost" title="connPoolMaxConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxConnsPerHost</span></code></a>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The parameter is separate from the connections in TaskExecutor
pools. See <a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxSize" title="ShardingTaskExecutorPoolMaxSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxSize</span></code></a>.</p>
</div>
<p><strong>Only</strong> adjust this setting if your driver does <em>not</em> pool
connections and you’re using authentication in the
context of a sharded cluster.</p>
<p>You can only set <a class="reference internal" href="#param.connPoolMaxConnsPerHost" title="connPoolMaxConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxConnsPerHost</span></code></a> during startup
in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">connPoolMaxConnsPerHost</span><span class="o">=</span><span class="m">250</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.connPoolMaxInUseConnsPerHost">
<code class="descname">connPoolMaxInUseConnsPerHost</code><a class="headerlink" href="#param.connPoolMaxInUseConnsPerHost" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.3.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the maximum number of in-use connections at any given time for
for outgoing connections to other <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instances in
the legacy global connection pool.</p>
<p>By default, the parameter is unset.</p>
<p>You can only set <a class="reference internal" href="#param.connPoolMaxInUseConnsPerHost" title="connPoolMaxInUseConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxInUseConnsPerHost</span></code></a> during
startup in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">connPoolMaxInUseConnsPerHost</span><span class="o">=</span><span class="m">100</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.connPoolMaxConnsPerHost" title="connPoolMaxConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxConnsPerHost</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.globalConnPoolIdleTimeoutMinutes">
<code class="descname">globalConnPoolIdleTimeoutMinutes</code><a class="headerlink" href="#param.globalConnPoolIdleTimeoutMinutes" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.3.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the time limit that connection in the legacy global connection
pool can remain idle before being closed.</p>
<p>By default, the parameter is unset.</p>
<p>You can only set <a class="reference internal" href="#param.globalConnPoolIdleTimeoutMinutes" title="globalConnPoolIdleTimeoutMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">globalConnPoolIdleTimeoutMinutes</span></code></a>
during startup in the config file or on the command line. For
example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">globalConnPoolIdleTimeoutMinutes</span><span class="o">=</span><span class="m">10</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.connPoolMaxShardedConnsPerHost" title="connPoolMaxShardedConnsPerHost"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">connPoolMaxShardedConnsPerHost</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.cursorTimeoutMillis">
<code class="descname">cursorTimeoutMillis</code><a class="headerlink" href="#param.cursorTimeoutMillis" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 600000 (i.e. 10 minutes)</p>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the expiration threshold in milliseconds for idle cursors
before MongoDB removes them; i.e. MongoDB removes cursors that have
been idle for the specified <a class="reference internal" href="#param.cursorTimeoutMillis" title="cursorTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">cursorTimeoutMillis</span></code></a>.</p>
<p>For example, the following sets the <a class="reference internal" href="#param.cursorTimeoutMillis" title="cursorTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">cursorTimeoutMillis</span></code></a>
to <code class="docutils literal"><span class="pre">300000</span></code> milliseconds (i.e. 5 minutes).</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">cursorTimeoutMillis</span><span class="o">=</span><span class="m">300000</span>
</pre></div>
</div>
</div>
<p>Or, if using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command within the
<a class="reference internal" href="program/mongo.html#bin.mongo" title="bin.mongo"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongo</span></code></a> shell:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">cursorTimeoutMillis</span><span class="o">:</span> <span class="mi">300000</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>Setting <a class="reference internal" href="#param.cursorTimeoutMillis" title="cursorTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">cursorTimeoutMillis</span></code></a> to less than or equal
to <code class="docutils literal"><span class="pre">0</span></code> results in all cursors being immediately eligible for timeout.
Generally, the timeout value should be greater than the average amount of
time for a query to return results. Use tools like the <a class="reference internal" href="method/cursor.explain.html#cursor.explain" title="cursor.explain()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">cursor.explain()</span></code></a>
cursor modifier to analyze the average query time and select an appropriate
timeout period.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.failIndexKeyTooLong">
<code class="descname">failIndexKeyTooLong</code><a class="headerlink" href="#param.failIndexKeyTooLong" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<div class="versionchanged">
<ul>
<span class="versionmodified">Changed in version 4.2: </span><li><p class="first">MongoDB removes the <a class="reference internal" href="limits.html#Index-Key-Limit" title="Index Key Limit"><code class="xref mongodb mongodb-limit docutils literal"><span class="pre">Index</span> <span class="pre">Key</span> <span class="pre">Limit</span></code></a> for
<a class="reference internal" href="command/setFeatureCompatibilityVersion.html#view-fcv"><span class="std std-ref">featureCompatibilityVersion</span></a> (fCV) set to
<code class="docutils literal"><span class="pre">&quot;4.2&quot;</span></code> or greater.</p>
</li>
<li><p class="first">In concert with the removal of the limit,
<code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexTooLong</span></code> only applies for MongoDB 2.6
through MongoDB versions with <a class="reference internal" href="command/setFeatureCompatibilityVersion.html#view-fcv"><span class="std std-ref">featureCompatibilityVersion</span></a> (fCV) set to <code class="docutils literal"><span class="pre">&quot;4.0&quot;</span></code> or earlier.</p>
</li>
</ul>
</div>
<p>For MongoDB 2.6 through MongoDB versions with
<code class="docutils literal"><span class="pre">featureCompatibilityVersion</span></code> (fCV) set to <code class="docutils literal"><span class="pre">&quot;4.0&quot;</span></code> or earlier,
<a class="reference internal" href="limits.html#Index-Key-Limit" title="Index Key Limit"><code class="xref mongodb mongodb-limit docutils literal"><span class="pre">Index</span> <span class="pre">Key</span> <span class="pre">Length</span> <span class="pre">Limit</span></code></a> applies. If you
attempt to insert or update a document whose index field exceeds
the <a class="reference internal" href="limits.html#Index-Key-Limit" title="Index Key Limit"><code class="xref mongodb mongodb-limit docutils literal"><span class="pre">Index</span> <span class="pre">Key</span> <span class="pre">Length</span> <span class="pre">Limit</span></code></a>, the operation
will fail and return an error to the client.</p>
<p>To avoid this issue, consider using <a class="reference internal" href="../core/index-hashed.html"><span class="doc">hashed indexes</span></a> or indexing a computed value. If you have an
existing data set and want to disable this behavior so you can
upgrade and then gradually resolve these indexing issues, you can
use <a class="reference internal" href="#param.failIndexKeyTooLong" title="failIndexKeyTooLong"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexKeyTooLong</span></code></a> to disable this behavior.</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">Setting <a class="reference internal" href="#param.failIndexKeyTooLong" title="failIndexKeyTooLong"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexKeyTooLong</span></code></a> to <code class="docutils literal"><span class="pre">false</span></code> is
a temporary workaround, not a permanent solution to the
problem of oversized index keys. With
<a class="reference internal" href="#param.failIndexKeyTooLong" title="failIndexKeyTooLong"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexKeyTooLong</span></code></a> set to <code class="docutils literal"><span class="pre">false</span></code>, queries can
return incomplete results if they use indexes that skip over
documents whose indexed fields exceed the
<a class="reference internal" href="limits.html#Index-Key-Limit" title="Index Key Limit"><code class="xref mongodb mongodb-limit docutils literal"><span class="pre">Index</span> <span class="pre">Key</span> <span class="pre">Length</span> <span class="pre">Limit</span></code></a>.</p>
</div>
<p><a class="reference internal" href="#param.failIndexKeyTooLong" title="failIndexKeyTooLong"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexKeyTooLong</span></code></a> defaults to <code class="docutils literal"><span class="pre">true</span></code>.</p>
<p>Issue the following command to disable the index key length
validation:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">failIndexKeyTooLong</span><span class="o">:</span> <span class="kc">false</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>You can also set <a class="reference internal" href="#param.failIndexKeyTooLong" title="failIndexKeyTooLong"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">failIndexKeyTooLong</span></code></a>  at
startup time with the following option:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">failIndexKeyTooLong</span><span class="o">=</span><span class="nb">false</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.notablescan">
<code class="descname">notablescan</code><a class="headerlink" href="#param.notablescan" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Specify whether <strong>all</strong> queries must use indexes. If <code class="docutils literal"><span class="pre">1</span></code>, MongoDB
will not execute queries that require a collection scan and will return an
error.</p>
<p>Consider the following example which sets <a class="reference internal" href="#param.notablescan" title="notablescan"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">notablescan</span></code></a> to <code class="docutils literal"><span class="pre">1</span></code>
or true:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">notablescan</span><span class="o">:</span> <span class="mi">1</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>Setting <a class="reference internal" href="#param.notablescan" title="notablescan"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">notablescan</span></code></a> to <code class="docutils literal"><span class="pre">1</span></code> can be useful for testing
application queries, for example, to identify queries that scan an
entire collection and cannot use an index.</p>
<p>To detect unindexed queries without <code class="docutils literal"><span class="pre">notablescan</span></code>, consider reading
the <a class="reference internal" href="../tutorial/evaluate-operation-performance.html"><span class="doc">Evaluate Performance of Current Operations</span></a> and
<a class="reference internal" href="../tutorial/optimize-query-performance-with-indexes-and-projections.html"><span class="doc">Optimize Query Performance</span></a>
sections and using the <a class="reference internal" href="#param.logLevel" title="logLevel"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logLevel</span></code></a> parameter,
<a class="reference internal" href="program/mongostat.html"><span class="doc">mongostat</span></a> and <a class="reference internal" href="../administration/analyzing-mongodb-performance.html#database-profiling"><span class="std std-ref">profiling</span></a>.</p>
<p>Don’t run production <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instances with
<a class="reference internal" href="#param.notablescan" title="notablescan"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">notablescan</span></code></a> because preventing collection scans can potentially
affect queries in all databases, including administrative queries.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ttlMonitorEnabled">
<code class="descname">ttlMonitorEnabled</code><a class="headerlink" href="#param.ttlMonitorEnabled" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>To support <a class="reference internal" href="../core/index-ttl.html"><span class="doc">TTL Indexes</span></a>, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>
instances have a background thread that is responsible for deleting
documents from collections with TTL indexes.</p>
<p>To disable this worker thread for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>, set
<a class="reference internal" href="#param.ttlMonitorEnabled" title="ttlMonitorEnabled"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ttlMonitorEnabled</span></code></a> to <code class="docutils literal"><span class="pre">false</span></code>, as in the following
operations:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">ttlMonitorEnabled</span><span class="o">:</span> <span class="kc">false</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>Alternately, you may disable the thread at startup time by starting the
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance with the following option:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">ttlMonitorEnabled</span><span class="o">=</span><span class="nb">false</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.disableJavaScriptJIT">
<code class="descname">disableJavaScriptJIT</code><a class="headerlink" href="#param.disableJavaScriptJIT" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionchanged">
<p><span class="versionmodified">Changed in version 4.0: </span>The JavaScript engine’s JIT compiler is now disabled by default.</p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>The MongoDB JavaScript engine uses SpiderMonkey, which implements
Just-in-Time (JIT) compilation for improved performance when running scripts.</p>
<p>To enable the JIT, set <a class="reference internal" href="#param.disableJavaScriptJIT" title="disableJavaScriptJIT"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">disableJavaScriptJIT</span></code></a> to <code class="docutils literal"><span class="pre">false</span></code>, as in
the following example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">disableJavaScriptJIT</span><span class="o">:</span> <span class="kc">false</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last"><a class="reference internal" href="operator/query/where.html#op._S_where" title="$where"><code class="xref mongodb mongodb-query docutils literal"><span class="pre">$where</span></code></a> will reuse existing JavaScript interpreter
contexts, so changes to <a class="reference internal" href="#param.disableJavaScriptJIT" title="disableJavaScriptJIT"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">disableJavaScriptJIT</span></code></a> may not
take effect immediately for these operations.</p>
</div>
<p>Alternately, you may enable the JIT at startup time by starting the
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance with the following option:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">disableJavaScriptJIT</span><span class="o">=</span><span class="nb">false</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.maxIndexBuildMemoryUsageMegabytes">
<code class="descname">maxIndexBuildMemoryUsageMegabytes</code><a class="headerlink" href="#param.maxIndexBuildMemoryUsageMegabytes" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
<p><em>Default</em>: 500</p>
<p>Limits the amount of memory that simultaneous index
builds on one collection may consume for the duration of the
builds. The specified amount of memory is shared between all
indexes built using a single
<a class="reference internal" href="command/createIndexes.html#dbcmd.createIndexes" title="createIndexes"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">createIndexes</span></code></a> command or its shell helper
<a class="reference internal" href="method/db.collection.createIndexes.html#db.collection.createIndexes" title="db.collection.createIndexes()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.collection.createIndexes()</span></code></a>.</p>
<p>The memory consumed by an index build is separate from the
WiredTiger cache memory (see
<a class="reference internal" href="configuration-options.html#storage.wiredTiger.engineConfig.cacheSizeGB" title="storage.wiredTiger.engineConfig.cacheSizeGB"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">cacheSizeGB</span></code></a>).</p>
<p>Index builds may be initiated either by a user command
such as <a class="reference internal" href="method/db.collection.createIndex.html"><span class="doc">Create Index</span></a>
or by an administrative process such as an
<a class="reference internal" href="../core/replica-set-sync.html"><span class="doc">initial sync</span></a>.
Both are subject to the limit set by
<a class="reference internal" href="#param.maxIndexBuildMemoryUsageMegabytes" title="maxIndexBuildMemoryUsageMegabytes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxIndexBuildMemoryUsageMegabytes</span></code></a>.</p>
<p>An <a class="reference internal" href="../core/replica-set-sync.html"><span class="doc">initial sync operation</span></a> populates
only one collection at a time and has no risk of exceeding the memory
limit. However, it is possible for a user to start index
builds on multiple collections in multiple databases simultaneously
and potentially consume an amount of memory greater than the limit
set in <a class="reference internal" href="#param.maxIndexBuildMemoryUsageMegabytes" title="maxIndexBuildMemoryUsageMegabytes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxIndexBuildMemoryUsageMegabytes</span></code></a>.</p>
<div class="admonition-tip admonition">
<p class="first admonition-title">Tip</p>
<p class="last">To minimize the impact of building an index on replica sets and
sharded clusters with replica set shards, use a rolling index build
procedure as described on
<a class="reference internal" href="../tutorial/build-indexes-on-replica-sets.html"><span class="doc">Build Indexes on Replica Sets</span></a>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 4.2.</span></p>
</div>
<ul class="simple">
<li>For <a class="reference internal" href="command/setFeatureCompatibilityVersion.html#view-fcv"><span class="std std-ref">feature compatibility version (fcv)</span></a> <code class="docutils literal"><span class="pre">&quot;4.2&quot;</span></code>,
the index build memory limit applies to all index builds.</li>
<li>For <a class="reference internal" href="command/setFeatureCompatibilityVersion.html#view-fcv"><span class="std std-ref">feature compatibility version (fcv)</span></a> <code class="docutils literal"><span class="pre">&quot;4.0&quot;</span></code>,
the index build memory limit only applies to foreground
index builds.</li>
</ul>
</dd></dl>

<dl class="parameter">
<dt id="param.reportOpWriteConcernCountersInServerStatus">
<code class="descname">reportOpWriteConcernCountersInServerStatus</code><a class="headerlink" href="#param.reportOpWriteConcernCountersInServerStatus" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.6.</span></p>
</div>
<p><em>Default</em>: false</p>
<p>A boolean flag that determines whether the
<a class="reference internal" href="method/db.serverStatus.html#db.serverStatus" title="db.serverStatus()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.serverStatus()</span></code></a> method and <a class="reference internal" href="command/serverStatus.html#dbcmd.serverStatus" title="serverStatus"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">serverStatus</span></code></a>
command return <a class="reference internal" href="command/serverStatus.html#serverstatus.opWriteConcernCounters" title="opWriteConcernCounters"><code class="xref mongodb mongodb-serverstatus docutils literal"><span class="pre">opWriteConcernCounters</span></code></a> information. <a class="footnote-reference" href="#perf" id="id2">[1]</a></p>
<p>You can only set
<a class="reference internal" href="#param.reportOpWriteConcernCountersInServerStatus" title="reportOpWriteConcernCountersInServerStatus"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">reportOpWriteConcernCountersInServerStatus</span></code></a> during
startup in the config file or on the command line. For example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">reportOpWriteConcernCountersInServerStatus</span><span class="o">=</span><span class="nb">true</span>
</pre></div>
</div>
</div>
<table class="docutils footnote" frame="void" id="perf" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id2">[1]</a></td><td>Enabling <a class="reference internal" href="#param.reportOpWriteConcernCountersInServerStatus" title="reportOpWriteConcernCountersInServerStatus"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">reportOpWriteConcernCountersInServerStatus</span></code></a>
can have a negative performance impact; specificaly, when running
<em>without</em> TLS.</td></tr>
</tbody>
</table>
</dd></dl>

<dl class="parameter">
<dt id="param.watchdogPeriodSeconds">
<code class="descname">watchdogPeriodSeconds</code><a class="headerlink" href="#param.watchdogPeriodSeconds" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: -1 (disabled)</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<ul class="last simple">
<li>Starting in MongoDB 4.2, the <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> is available in both the Community and
MongoDB Enterprise editions.</li>
<li>In earlier versions (3.2.16+, 3.4.7+, 3.6.0+, 4.0.0+), the
<a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> is only
available in MongoDB Enterprise edition.</li>
</ul>
</div>
<p>Determines how frequent the <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> checks the status of the monitored
filesystems:</p>
<ul class="simple">
<li>The <a class="reference internal" href="program/mongod.html#cmdoption-mongod-dbpath"><code class="xref std std-option docutils literal"><span class="pre">--dbpath</span></code></a> directory</li>
<li>The <code class="docutils literal"><span class="pre">journal</span></code> directory inside the <a class="reference internal" href="program/mongod.html#cmdoption-mongod-dbpath"><code class="xref std std-option docutils literal"><span class="pre">--dbpath</span></code></a> directory if
<a class="reference internal" href="program/mongod.html#cmdoption-mongod-journal"><code class="xref std std-option docutils literal"><span class="pre">journaling</span></code></a> is enabled</li>
<li>The directory of <a class="reference internal" href="program/mongod.html#cmdoption-mongod-logpath"><code class="xref std std-option docutils literal"><span class="pre">--logpath</span></code></a> file</li>
<li>The directory of <a class="reference internal" href="program/mongod.html#cmdoption-mongod-auditpath"><code class="xref std std-option docutils literal"><span class="pre">--auditPath</span></code></a> file</li>
</ul>
<p>Valid values for <a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> are:</p>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">-1</span></code> (the default), to disable/pause <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a>, or</li>
<li>An integer greater than or equal to 60.</li>
</ul>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<ul class="last simple">
<li>If a filesystem on a monitored directory becomes unresponsive,
it can take a maximum of nearly <em>twice</em> the value of
<a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> to terminate the
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>.</li>
<li>If any of its monitored directory is a symlink to other
volumes, the Storage Node Watchdog does not monitor the symlink
target. For example, if the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> uses
<a class="reference internal" href="configuration-options.html#storage.directoryPerDB" title="storage.directoryPerDB"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.directoryPerDB:</span> <span class="pre">true</span></code></a> (or <a class="reference internal" href="program/mongod.html#cmdoption-mongod-directoryperdb"><code class="xref std std-option docutils literal"><span class="pre">--directoryperdb</span></code></a>) and symlinks a database directory to
another volume, the Storage Node Watchdog does not follow the
symlink to monitor the target.</li>
</ul>
</div>
<p>To enable <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a>,
<a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> must be set during startup.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">watchdogPeriodSeconds</span><span class="o">=</span><span class="m">60</span>
</pre></div>
</div>
</div>
<p>You can only enable the <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> at startup. However, once enabled, you can
pause the <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> or
change the <a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> during runtime.</p>
<p>Once enabled,</p>
<ul>
<li><p class="first">To pause the <a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a>
during runtime, set <a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> to -1.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">watchdogPeriodSeconds</span><span class="o">:</span> <span class="o">-</span><span class="mi">1</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</li>
<li><p class="first">To resume or change the period during runtime, set
<a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> to a number greater than or
equal to 60.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">watchdogPeriodSeconds</span><span class="o">:</span> <span class="mi">120</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</li>
</ul>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">It is an error to set <a class="reference internal" href="#param.watchdogPeriodSeconds" title="watchdogPeriodSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">watchdogPeriodSeconds</span></code></a> at runtime if the
<a class="reference internal" href="../administration/monitoring.html#storage-node-watchdog"><span class="std std-ref">Storage Node Watchdog</span></a> was not enabled at
startup time.</p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.tcmallocReleaseRate">
<code class="descname">tcmallocReleaseRate</code><a class="headerlink" href="#param.tcmallocReleaseRate" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.3: </span><em>Also available in 3.6.17+ and 4.0.14+</em></p>
</div>
<p>Default: 1.0</p>
<p>Specifies the tcmalloc release rate (<a class="reference external" href="https://gperftools.github.io/gperftools/tcmalloc.html#runtime">TCMALLOC_RELEASE_RATE</a>).
Per <a class="reference external" href="https://gperftools.github.io/gperftools/tcmalloc.html#runtime">https://gperftools.github.io/gperftools/tcmalloc.html#runtime</a>
TCMALLOC_RELEASE_RATE is described as:</p>
<blockquote class="epigraph">
<div><p>Rate at which we release unused memory to the system, via
madvise(MADV_DONTNEED), on systems that support it. Zero means we
never release memory back to the system. Increase this flag to
return memory faster; decrease it to return memory slower.
Reasonable rates are in the range [0,10].</p>
<p class="attribution">&mdash;<a class="reference external" href="https://gperftools.github.io/gperftools/tcmalloc.html#runtime">https://gperftools.github.io/gperftools/tcmalloc.html#runtime</a></p>
</div></blockquote>
<p>To modify the release rate during runtime, you can use the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command; for example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">tcmallocReleaseRate</span><span class="o">:</span> <span class="mf">5.0</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>You can also set <a class="reference internal" href="#param.tcmallocReleaseRate" title="tcmallocReleaseRate"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">tcmallocReleaseRate</span></code></a> at startup time;
for example:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="s2">&quot;tcmallocReleaseRate=5.0&quot;</span>
</pre></div>
</div>
</div>
</dd></dl>

</div>
<div class="section" id="logging-parameters">
<h3>Logging Parameters<a class="headerlink" href="#logging-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.logLevel">
<code class="descname">logLevel</code><a class="headerlink" href="#param.logLevel" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Specify an integer between <code class="docutils literal"><span class="pre">0</span></code> and <code class="docutils literal"><span class="pre">5</span></code> signifying the verbosity
of the <a class="reference internal" href="log-messages.html"><span class="doc">logging</span></a>, where <code class="docutils literal"><span class="pre">5</span></code> is the
most verbose. <a class="footnote-reference" href="#log-message" id="id3">[2]</a></p>
<p>The default <a class="reference internal" href="#param.logLevel" title="logLevel"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logLevel</span></code></a> is <code class="docutils literal"><span class="pre">0</span></code> (Informational).</p>
<p>The following example sets the <a class="reference internal" href="#param.logLevel" title="logLevel"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logLevel</span></code></a> to <code class="docutils literal"><span class="pre">2</span></code>:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">logLevel</span><span class="o">:</span> <span class="mi">2</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<ul class="last simple">
<li><a class="reference internal" href="#param.logComponentVerbosity" title="logComponentVerbosity"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logComponentVerbosity</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.verbosity" title="systemLog.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.verbosity</span></code></a></li>
</ul>
</div>
<table class="docutils footnote" frame="void" id="log-message" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id3">[2]</a></td><td>Starting in version 4.2, MongoDB includes the Debug verbosity level
(1-5) in the <a class="reference internal" href="log-messages.html#log-severity-levels"><span class="std std-ref">log messages</span></a>. For example,
if the verbosity level is 2, MongoDB logs <code class="docutils literal"><span class="pre">D2</span></code>. In previous
versions, MongoDB log messages only specified <code class="docutils literal"><span class="pre">D</span></code> for Debug level.</td></tr>
</tbody>
</table>
</dd></dl>

<dl class="parameter">
<dt id="param.logComponentVerbosity">
<code class="descname">logComponentVerbosity</code><a class="headerlink" href="#param.logComponentVerbosity" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets the verbosity levels of various <a class="reference internal" href="log-messages.html#log-message-components"><span class="std std-ref">components</span></a> for <a class="reference internal" href="log-messages.html"><span class="doc">log messages</span></a>. The verbosity level determines the
amount of <a class="reference internal" href="log-messages.html#log-severity-levels"><span class="std std-ref">Informational and Debug</span></a>
messages MongoDB outputs. <a class="footnote-reference" href="#log-message2" id="id4">[3]</a></p>
<p>The verbosity level can range from <code class="docutils literal"><span class="pre">0</span></code> to <code class="docutils literal"><span class="pre">5</span></code>:</p>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">0</span></code> is the MongoDB’s default log verbosity level, to include
<a class="reference internal" href="log-messages.html#log-severity-levels"><span class="std std-ref">Informational</span></a> messages.</li>
<li><code class="docutils literal"><span class="pre">1</span></code> to <code class="docutils literal"><span class="pre">5</span></code> increases the verbosity level to include
<a class="reference internal" href="log-messages.html#log-severity-levels"><span class="std std-ref">Debug</span></a> messages.</li>
</ul>
<p>For a component, you can also specify <code class="docutils literal"><span class="pre">-1</span></code> to inherit the parent’s
verbosity level.</p>
<p>To specify the verbosity level, use a document similar to the
following:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-none"><div class="highlight"><pre><span></span>{
  verbosity: &lt;int&gt;,
  &lt;component1&gt;: { verbosity: &lt;int&gt; },
  &lt;component2&gt;: {
     verbosity: &lt;int&gt;,
     &lt;component3&gt;: { verbosity: &lt;int&gt; }
  },
  ...
}
</pre></div>
</div>
</div>
<p>For the components, you can specify just the <code class="docutils literal"><span class="pre">&lt;component&gt;:</span> <span class="pre">&lt;int&gt;</span></code>
in the document, unless you are setting both the parent verbosity
level and that of the child component(s) as well:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-none"><div class="highlight"><pre><span></span>{
  verbosity: &lt;int&gt;,
  &lt;component1&gt;: &lt;int&gt; ,
  &lt;component2&gt;: {
     verbosity: &lt;int&gt;,
     &lt;component3&gt;: &lt;int&gt;
  }
  ...
}
</pre></div>
</div>
</div>
<p>The top-level <code class="docutils literal"><span class="pre">verbosity</span></code> field corresponds to
<a class="reference internal" href="configuration-options.html#systemLog.verbosity" title="systemLog.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.verbosity</span></code></a> which sets the default level for all
components. The default value of <a class="reference internal" href="configuration-options.html#systemLog.verbosity" title="systemLog.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.verbosity</span></code></a> is
<code class="docutils literal"><span class="pre">0</span></code>.</p>
<p>The components correspond to the following settings:</p>
<ul class="simple">
<li><a class="reference internal" href="configuration-options.html#systemLog.component.accessControl.verbosity" title="systemLog.component.accessControl.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">accessControl</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.command.verbosity" title="systemLog.component.command.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">command</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.control.verbosity" title="systemLog.component.control.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">control</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.ftdc.verbosity" title="systemLog.component.ftdc.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">ftdc</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.geo.verbosity" title="systemLog.component.geo.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">geo</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.index.verbosity" title="systemLog.component.index.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">index</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.network.verbosity" title="systemLog.component.network.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">network</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.query.verbosity" title="systemLog.component.query.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">query</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.replication.verbosity" title="systemLog.component.replication.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">replication</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.replication.election.verbosity" title="systemLog.component.replication.election.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">replication.election</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.replication.heartbeats.verbosity" title="systemLog.component.replication.heartbeats.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">replication.heartbeats</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.replication.initialSync.verbosity" title="systemLog.component.replication.initialSync.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">replication.initialSync</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.replication.rollback.verbosity" title="systemLog.component.replication.rollback.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">replication.rollback</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.storage.recovery.verbosity" title="systemLog.component.storage.recovery.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">recovery</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.sharding.verbosity" title="systemLog.component.sharding.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">sharding</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.storage.verbosity" title="systemLog.component.storage.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.storage.journal.verbosity" title="systemLog.component.storage.journal.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.journal</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.transaction.verbosity" title="systemLog.component.transaction.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">transaction</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.write.verbosity" title="systemLog.component.write.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">write</span></code></a></li>
</ul>
<p>Unless explicitly set, the component has the verbosity level of its
parent. For example, <code class="docutils literal"><span class="pre">storage</span></code> is the parent of
<code class="docutils literal"><span class="pre">storage.journal</span></code>. That is, if you specify a <a class="reference internal" href="configuration-options.html#systemLog.component.storage.verbosity" title="systemLog.component.storage.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage</span></code></a> verbosity level, this level
also applies to:</p>
<ul class="simple">
<li><a class="reference internal" href="configuration-options.html#systemLog.component.storage.journal.verbosity" title="systemLog.component.storage.journal.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.journal</span></code></a> components
<em>unless</em> you specify the verbosity level for
<a class="reference internal" href="configuration-options.html#systemLog.component.storage.journal.verbosity" title="systemLog.component.storage.journal.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.journal</span></code></a>.</li>
<li><a class="reference internal" href="configuration-options.html#systemLog.component.storage.recovery.verbosity" title="systemLog.component.storage.recovery.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.recovery</span></code></a> components
<em>unless</em> you specify the verbosity level for
<a class="reference internal" href="configuration-options.html#systemLog.component.storage.recovery.verbosity" title="systemLog.component.storage.recovery.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.recovery</span></code></a>.</li>
</ul>
<p>For example, the following sets the <a class="reference internal" href="configuration-options.html#systemLog.verbosity" title="systemLog.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">default</span> <span class="pre">verbosity</span>
<span class="pre">level</span></code></a> to <code class="docutils literal"><span class="pre">1</span></code>, the <a class="reference internal" href="configuration-options.html#systemLog.component.query.verbosity" title="systemLog.component.query.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">query</span></code></a> to <code class="docutils literal"><span class="pre">2</span></code>, the
<a class="reference internal" href="configuration-options.html#systemLog.component.storage.verbosity" title="systemLog.component.storage.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage</span></code></a> to <code class="docutils literal"><span class="pre">2</span></code>,
and the <a class="reference internal" href="configuration-options.html#systemLog.component.storage.journal.verbosity" title="systemLog.component.storage.journal.verbosity"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.journal</span></code></a> to <code class="docutils literal"><span class="pre">1</span></code>.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span>
   <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span>
   <span class="nx">logComponentVerbosity</span><span class="o">:</span> <span class="p">{</span>
      <span class="nx">verbosity</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span>
      <span class="nx">query</span><span class="o">:</span> <span class="p">{</span> <span class="nx">verbosity</span><span class="o">:</span> <span class="mi">2</span> <span class="p">},</span>
      <span class="nx">storage</span><span class="o">:</span> <span class="p">{</span>
         <span class="nx">verbosity</span><span class="o">:</span> <span class="mi">2</span><span class="p">,</span>
         <span class="nx">journal</span><span class="o">:</span> <span class="p">{</span>
            <span class="nx">verbosity</span><span class="o">:</span> <span class="mi">1</span>
         <span class="p">}</span>
      <span class="p">}</span>
   <span class="p">}</span>
<span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>You can also set parameter <a class="reference internal" href="#param.logComponentVerbosity" title="logComponentVerbosity"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logComponentVerbosity</span></code></a> at
startup time, passing the verbosity level document as a string.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="s2">&quot;logComponentVerbosity={command: 3}&quot;</span>
</pre></div>
</div>
</div>
<p>The <a class="reference internal" href="program/mongo.html#bin.mongo" title="bin.mongo"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongo</span></code></a> shell also provides the <a class="reference internal" href="method/db.setLogLevel.html#db.setLogLevel" title="db.setLogLevel()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">db.setLogLevel()</span></code></a>
to set the log level for a single component. For various ways to set
the log verbosity level, see <a class="reference internal" href="log-messages.html#log-messages-configure-verbosity"><span class="std std-ref">Configure Log Verbosity Levels</span></a>.</p>
<table class="docutils footnote" frame="void" id="log-message2" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id4">[3]</a></td><td>Starting in version 4.2, MongoDB includes the Debug verbosity level
(1-5) in the <a class="reference internal" href="log-messages.html#log-severity-levels"><span class="std std-ref">log messages</span></a>. For example,
if the verbosity level is 2, MongoDB logs <code class="docutils literal"><span class="pre">D2</span></code>. In previous
versions, MongoDB log messages only specified <code class="docutils literal"><span class="pre">D</span></code> for Debug level.</td></tr>
</tbody>
</table>
</dd></dl>

<dl class="parameter">
<dt id="param.maxLogSizeKB">
<code class="descname">maxLogSizeKB</code><a class="headerlink" href="#param.maxLogSizeKB" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 10</p>
<p>Specifies the maximum size, in kilobytes, for a log line. Lines exceeding
this limit print only the beginning and end of the line, excising the middle
portion.</p>
<p>For example, the following sets the maximum size to <code class="docutils literal"><span class="pre">20</span></code> kilobytes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">maxLogSizeKB</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">Using a large value for <a class="reference internal" href="#param.maxLogSizeKB" title="maxLogSizeKB"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxLogSizeKB</span></code></a> may adversely affect
system performance and negatively impact database operations.</p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.quiet">
<code class="descname">quiet</code><a class="headerlink" href="#param.quiet" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Sets quiet logging mode. If
<code class="docutils literal"><span class="pre">1</span></code>, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> will go into a quiet logging
mode which will not log the following events/activities:</p>
<ul class="simple">
<li>connection events;</li>
<li>the <a class="reference internal" href="command/drop.html#dbcmd.drop" title="drop"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">drop</span></code></a> command, the
<a class="reference internal" href="command/dropIndexes.html#dbcmd.dropIndexes" title="dropIndexes"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">dropIndexes</span></code></a> command, the
<a class="reference internal" href="command/diagLogging.html#dbcmd.diagLogging" title="diagLogging"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">diagLogging</span></code></a> command, the
<a class="reference internal" href="command/validate.html#dbcmd.validate" title="validate"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">validate</span></code></a> command, and the
<a class="reference internal" href="command/clean.html#dbcmd.clean" title="clean"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">clean</span></code></a> command; and</li>
<li>replication synchronization activities.</li>
</ul>
<p>Consider the following example which sets the
<code class="docutils literal"><span class="pre">quiet</span></code> to <code class="docutils literal"><span class="pre">1</span></code>:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">quiet</span><span class="o">:</span> <span class="mi">1</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="configuration-options.html#systemLog.quiet" title="systemLog.quiet"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.quiet</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.redactClientLogData">
<code class="descname">redactClientLogData</code><a class="headerlink" href="#param.redactClientLogData" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.4.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: boolean</p>
<div class="admonition-enterprise-feature admonition">
<p class="first admonition-title">Enterprise Feature</p>
<p class="last">Available in MongoDB Enterprise only.</p>
</div>
<p>Configure the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> to
redact any message accompanying a given log event before logging.
This prevents the program from writing potentially sensitive data
stored on the database to the diagnostic log. Metadata such as error
or operation codes, line numbers, and source file names are still
visible in the logs.</p>
<p>Use <a class="reference internal" href="#param.redactClientLogData" title="redactClientLogData"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">redactClientLogData</span></code></a> in conjunction with
<a class="reference internal" href="../core/security-encryption-at-rest.html"><span class="doc">Encryption at Rest</span></a> and
<a class="reference internal" href="../core/security-transport-encryption.html"><span class="doc">TLS/SSL (Transport Encryption)</span></a> to assist compliance with
regulatory requirements.</p>
<p>To enable log redaction on a running <code class="docutils literal"><span class="pre">mongod</span></code> or
<code class="docutils literal"><span class="pre">mongos</span></code>, use the following command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">redactClientLogData</span> <span class="o">:</span> <span class="kc">true</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="configuration-options.html#security.redactClientLogData" title="security.redactClientLogData"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">security.redactClientLogData</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.traceExceptions">
<code class="descname">traceExceptions</code><a class="headerlink" href="#param.traceExceptions" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Configures <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> to log full source code stack traces
for every database and socket C++ exception, for use with debugging.
If <code class="docutils literal"><span class="pre">true</span></code>, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> will log full stack traces.</p>
<p>Consider the following example which sets the
<code class="docutils literal"><span class="pre">traceExceptions</span></code> to <code class="docutils literal"><span class="pre">true</span></code>:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">traceExceptions</span><span class="o">:</span> <span class="kc">true</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="configuration-options.html#systemLog.traceAllExceptions" title="systemLog.traceAllExceptions"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.traceAllExceptions</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.suppressNoTLSPeerCertificateWarning">
<code class="descname">suppressNoTLSPeerCertificateWarning</code><a class="headerlink" href="#param.suppressNoTLSPeerCertificateWarning" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.1.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: boolean</p>
<p><em>Default</em>: false</p>
<p>By default, a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> with
<a class="reference internal" href="../tutorial/configure-ssl.html"><span class="doc">TLS/SSL enabled</span></a> and
<a class="reference internal" href="configuration-options.html#net.ssl.allowConnectionsWithoutCertificates" title="net.ssl.allowConnectionsWithoutCertificates"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">net.ssl.allowConnectionsWithoutCertificates</span></code></a> : <code class="docutils literal"><span class="pre">true</span></code>
lets clients connect without providing a certificate for
validation while logging an warning. Set
<code class="docutils literal"><span class="pre">suppressNoTLSPeerCertificateWarning</span></code> to <code class="docutils literal"><span class="pre">1</span></code> or <code class="docutils literal"><span class="pre">true</span></code> to
suppress those warnings.</p>
<p>The following operation sets <code class="docutils literal"><span class="pre">suppressNoTLSPeerCertificateWarning</span></code>
to <code class="docutils literal"><span class="pre">true</span></code>:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, suppressNoTLSPeerCertificateWarning: true<span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
</dd></dl>

</div>
<div class="section" id="diagnostic-parameters">
<span id="param-ftdc"></span><h3>Diagnostic Parameters<a class="headerlink" href="#diagnostic-parameters" title="Permalink to this headline">¶</a></h3>
<p>To facilitate analysis of the MongoDB server behavior by MongoDB
engineers, MongoDB logs server statistics to diagnostic files at
periodic intervals.</p>
<p>For <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>, the diagnostic data files are stored in the
<code class="docutils literal"><span class="pre">diagnostic.data</span></code> directory under the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance’s
<code class="docutils literal"><span class="pre">--dbpath</span></code> or <a class="reference internal" href="configuration-options.html#storage.dbPath" title="storage.dbPath"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.dbPath</span></code></a>.</p>
<p>For <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>, the diagnostic data files, by default, are
stored in a directory under the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s
<code class="docutils literal"><span class="pre">--logpath</span></code> or <a class="reference internal" href="configuration-options.html#systemLog.path" title="systemLog.path"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.path</span></code></a> directory. The diagnostic
data directory is computed by truncating the logpath’s file
extension(s) and concatenating <code class="docutils literal"><span class="pre">diagnostic.data</span></code> to the remaining
name.</p>
<p>For example, if <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> has <code class="docutils literal"><span class="pre">--logpath</span>
<span class="pre">/var/log/mongodb/mongos.log.201708015</span></code>, then the diagnostic data
directory is <code class="docutils literal"><span class="pre">/var/log/mongodb/mongos.diagnostic.data/</span></code> directory. To
specify a different diagnostic data directory for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>,
set the <a class="reference internal" href="#param.diagnosticDataCollectionDirectoryPath" title="diagnosticDataCollectionDirectoryPath"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionDirectoryPath</span></code></a> parameter.</p>
<p>The following parameters support diagnostic data capture (FTDC):</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The default values for the diagnostic data capture interval and the
maximum sizes are chosen to provide useful data to MongoDB engineers
with minimal impact on performance and storage size. Typically, these
values will only need modifications as requested by MongoDB engineers
for specific diagnostic purposes.</p>
</div>
<dl class="parameter">
<dt id="param.diagnosticDataCollectionEnabled">
<code class="descname">diagnosticDataCollectionEnabled</code><a class="headerlink" href="#param.diagnosticDataCollectionEnabled" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4.14: </span>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
</div>
<p><em>Type</em>: boolean</p>
<p><em>Default</em>: true</p>
<p>Determines whether to enable the collecting and logging of data for
diagnostic purposes. Diagnostic logging is enabled by default.</p>
<p>For example, the following disables the diagnostic collection:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">diagnosticDataCollectionEnabled</span><span class="o">=</span><span class="nb">false</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.diagnosticDataCollectionDirectoryPath">
<code class="descname">diagnosticDataCollectionDirectoryPath</code><a class="headerlink" href="#param.diagnosticDataCollectionDirectoryPath" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.4.14.</span></p>
</div>
<p><em>Type</em>: String</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Specify the directory for the diagnostic directory for
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>. If the directory does not exist,
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> creates the directory.</p>
<p>If unspecified, the diagnostic data directory is computed by
truncating the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s <code class="docutils literal"><span class="pre">--logpath</span></code> or
<a class="reference internal" href="configuration-options.html#systemLog.path" title="systemLog.path"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">systemLog.path</span></code></a> file extension(s) and concatenating
<code class="docutils literal"><span class="pre">diagnostic.data</span></code>.</p>
<p>For example, if <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> has <code class="docutils literal"><span class="pre">--logpath</span>
<span class="pre">/var/log/mongodb/mongos.log.201708015</span></code>, then the diagnostic data
directory is <code class="docutils literal"><span class="pre">/var/log/mongodb/mongos.diagnostic.data/</span></code>.</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">If <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> cannot create the specified directory, e.g.
a file exists with the same name in the path or the process does
not have permissions to create the directory, the diagnostic data
capture will be disabled for that instance.</p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.diagnosticDataCollectionDirectorySizeMB">
<code class="descname">diagnosticDataCollectionDirectorySizeMB</code><a class="headerlink" href="#param.diagnosticDataCollectionDirectorySizeMB" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4: </span>Increased default size to 200 megabytes.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4.14: </span>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 200</p>
<p>Specifies the maximum size, in megabytes, of the <code class="docutils literal"><span class="pre">diagnostic.data</span></code>
directory. If directory size exceeds this number, the oldest
<a class="reference internal" href="../release-notes/3.2.html#diagnostic-data-capture"><span class="std std-ref">diagnostic files in the directory</span></a> are automatically deleted based on
the timestamp in the file name.</p>
<p>For example, the following sets the maximum size of the directory to
<code class="docutils literal"><span class="pre">250</span></code> megabytes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">diagnosticDataCollectionDirectorySizeMB</span><span class="o">=</span><span class="m">250</span>
</pre></div>
</div>
</div>
<p>The minimum value for
<a class="reference internal" href="#param.diagnosticDataCollectionDirectorySizeMB" title="diagnosticDataCollectionDirectorySizeMB"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionDirectorySizeMB</span></code></a> is <code class="docutils literal"><span class="pre">10</span></code>
megabytes. <a class="reference internal" href="#param.diagnosticDataCollectionDirectorySizeMB" title="diagnosticDataCollectionDirectorySizeMB"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionDirectorySizeMB</span></code></a> must
be greater than maximum diagnostic file size
<a class="reference internal" href="#param.diagnosticDataCollectionFileSizeMB" title="diagnosticDataCollectionFileSizeMB"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionFileSizeMB</span></code></a>.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.diagnosticDataCollectionFileSizeMB">
<code class="descname">diagnosticDataCollectionFileSizeMB</code><a class="headerlink" href="#param.diagnosticDataCollectionFileSizeMB" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4.14: </span>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 10</p>
<p>Specifies the maximum size, in megabytes, of each <a class="reference internal" href="../release-notes/3.2.html#diagnostic-data-capture"><span class="std std-ref">diagnostic
file</span></a>. If the file exceeds the maximum
file size, MongoDB creates a new file.</p>
<p>For example, the following sets the maximum size of each diagnostic
file to <code class="docutils literal"><span class="pre">20</span></code> megabytes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">diagnosticDataCollectionFileSizeMB</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
<p>The minimum value for
<a class="reference internal" href="#param.diagnosticDataCollectionFileSizeMB" title="diagnosticDataCollectionFileSizeMB"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionFileSizeMB</span></code></a> is <code class="docutils literal"><span class="pre">1</span></code> megabyte.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.diagnosticDataCollectionPeriodMillis">
<code class="descname">diagnosticDataCollectionPeriodMillis</code><a class="headerlink" href="#param.diagnosticDataCollectionPeriodMillis" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.4.14: </span>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 1000</p>
<p>Specifies the interval, in milliseconds, at which to collect
diagnostic data.</p>
<p>For example, the following sets the interval to
<code class="docutils literal"><span class="pre">5000</span></code> milliseconds or 5 seconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">diagnosticDataCollectionPeriodMillis</span><span class="o">=</span><span class="m">5000</span>
</pre></div>
</div>
</div>
<p>The minimum value for
<a class="reference internal" href="#param.diagnosticDataCollectionPeriodMillis" title="diagnosticDataCollectionPeriodMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">diagnosticDataCollectionPeriodMillis</span></code></a> is <code class="docutils literal"><span class="pre">100</span></code>
milliseconds.</p>
</dd></dl>

</div>
<div class="section" id="logical-session-parameters">
<h3>Logical Session Parameters<a class="headerlink" href="#logical-session-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.logicalSessionRefreshMillis">
<code class="descname">logicalSessionRefreshMillis</code><a class="headerlink" href="#param.logicalSessionRefreshMillis" title="Permalink to this definition">¶</a></dt>
<dd><div class="note admonition">
<p class="first admonition-title">Availability</p>
<p class="last">New in version 4.0.4 (and version 3.6.9).</p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 300000 (i.e. 5 minutes)</p>
<p>The interval (in milliseconds) at which the cache refreshes its logical
session records against the main session store.</p>
<p>You can only set <a class="reference internal" href="#param.logicalSessionRefreshMillis" title="logicalSessionRefreshMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logicalSessionRefreshMillis</span></code></a> at
startup and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command.</p>
<p>For example, to set the <a class="reference internal" href="#param.logicalSessionRefreshMillis" title="logicalSessionRefreshMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">logicalSessionRefreshMillis</span></code></a>
for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance to 10 minutes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">logicalSessionRefreshMillis</span><span class="o">=</span><span class="m">600000</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.localLogicalSessionTimeoutMinutes">
<code class="descname">localLogicalSessionTimeoutMinutes</code><a class="headerlink" href="#param.localLogicalSessionTimeoutMinutes" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 30</p>
<div class="warning admonition">
<p class="first admonition-title">For testing purposes only</p>
<p class="last">This parameter is intended for testing purposes only and not for
production use.</p>
</div>
<p>The time in minutes that a <a class="reference internal" href="../core/read-isolation-consistency-recency.html#sessions"><span class="std std-ref">session</span></a> remains active
after its most recent use. Sessions that have not received a new
read/write operation from the client or been refreshed with
<a class="reference internal" href="command/refreshSessions.html#dbcmd.refreshSessions" title="refreshSessions"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">refreshSessions</span></code></a> within this threshold are cleared from the
cache. State associated with an expired session may be cleaned up by the
server at any time.</p>
<p>This parameter applies only to the instance on which it is set. To
set this parameter on replica sets and sharded clusters, you must
specify the same value on every member; otherwise, sessions will
not function properly.</p>
<p>You can only set <a class="reference internal" href="#param.localLogicalSessionTimeoutMinutes" title="localLogicalSessionTimeoutMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">localLogicalSessionTimeoutMinutes</span></code></a> at
startup and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command.</p>
<p>For example, to set the <a class="reference internal" href="#param.localLogicalSessionTimeoutMinutes" title="localLogicalSessionTimeoutMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">localLogicalSessionTimeoutMinutes</span></code></a>
for a test <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance to 20 minutes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">localLogicalSessionTimeoutMinutes</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.maxAcceptableLogicalClockDriftSecs">
<code class="descname">maxAcceptableLogicalClockDriftSecs</code><a class="headerlink" href="#param.maxAcceptableLogicalClockDriftSecs" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 31536000 (1 year)</p>
<p>The maximum amount by which the current cluster time can be advanced;
i.e., <a class="reference internal" href="#param.maxAcceptableLogicalClockDriftSecs" title="maxAcceptableLogicalClockDriftSecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxAcceptableLogicalClockDriftSecs</span></code></a> is the maximum
difference between the new value of the cluster time and the current
cluster time. Cluster time is a logical time used for ordering of
operations.</p>
<p>You cannot advance the cluster time to a new value if the new
cluster time differs from the current cluster time by more than
<a class="reference internal" href="#param.maxAcceptableLogicalClockDriftSecs" title="maxAcceptableLogicalClockDriftSecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxAcceptableLogicalClockDriftSecs</span></code></a>,</p>
<p>You can only set <a class="reference internal" href="#param.maxAcceptableLogicalClockDriftSecs" title="maxAcceptableLogicalClockDriftSecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxAcceptableLogicalClockDriftSecs</span></code></a> at
startup and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command.</p>
<p>For example, to set the <a class="reference internal" href="#param.maxAcceptableLogicalClockDriftSecs" title="maxAcceptableLogicalClockDriftSecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxAcceptableLogicalClockDriftSecs</span></code></a>
for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance to 15 minutes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">maxAcceptableLogicalClockDriftSecs</span><span class="o">=</span><span class="m">900</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.maxSessions">
<code class="descname">maxSessions</code><a class="headerlink" href="#param.maxSessions" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.1.</span></p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 1000000</p>
<p>The maximum number of sessions that can be cached.</p>
<p>You can only set <a class="reference internal" href="#param.maxSessions" title="maxSessions"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxSessions</span></code></a> during start-up.</p>
<p>For example, to set the <a class="reference internal" href="#param.maxSessions" title="maxSessions"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxSessions</span></code></a>
for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance to 1000:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">maxSessions</span><span class="o">=</span><span class="m">1000</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.TransactionRecordMinimumLifetimeMinutes">
<code class="descname">TransactionRecordMinimumLifetimeMinutes</code><a class="headerlink" href="#param.TransactionRecordMinimumLifetimeMinutes" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 30</p>
<p>The minimum lifetime a transaction record exists in the
<a class="reference internal" href="config-database.html#config.transactions" title="config.transactions"><code class="xref mongodb mongodb-data docutils literal"><span class="pre">transactions</span></code></a> collection before the record becomes
eligible for cleanup.</p>
<p>You can only set <a class="reference internal" href="#param.TransactionRecordMinimumLifetimeMinutes" title="TransactionRecordMinimumLifetimeMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">TransactionRecordMinimumLifetimeMinutes</span></code></a> at
startup and cannot change this setting with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command.</p>
<p>For example, to set the <a class="reference internal" href="#param.TransactionRecordMinimumLifetimeMinutes" title="TransactionRecordMinimumLifetimeMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">TransactionRecordMinimumLifetimeMinutes</span></code></a>
for a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance to 20 minutes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">TransactionRecordMinimumLifetimeMinutes</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.localLogicalSessionTimeoutMinutes" title="localLogicalSessionTimeoutMinutes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">localLogicalSessionTimeoutMinutes</span></code></a></p>
</div>
</dd></dl>

</div>
<div class="section" id="replication-parameters">
<h3>Replication Parameters<a class="headerlink" href="#replication-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.enableFlowControl">
<code class="descname">enableFlowControl</code><a class="headerlink" href="#param.enableFlowControl" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p><em>Type</em>: boolean</p>
<p><em>Default</em>: true</p>
<p>Enables or disables the mechanism that controls the rate at which the
primary applies its writes with the goal of keeping the secondary members’
<a class="reference internal" href="command/replSetGetStatus.html#replSetGetStatus.optimes.lastCommittedOpTime" title="replSetGetStatus.optimes.lastCommittedOpTime"><code class="xref mongodb mongodb-data docutils literal"><span class="pre">majority</span> <span class="pre">committed</span></code></a> lag under a
configurable maximum value.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">For flow control to engage, the replica set/sharded cluster must
have: <a class="reference internal" href="command/setFeatureCompatibilityVersion.html#view-fcv"><span class="std std-ref">featureCompatibilityVersion (FCV)</span></a> of
<code class="docutils literal"><span class="pre">4.2</span></code> and read concern <a class="reference internal" href="configuration-options.html#replication.enableMajorityReadConcern" title="replication.enableMajorityReadConcern"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">majority</span> <span class="pre">enabled</span></code></a>. That is, enabled flow
control has no effect if FCV is not <code class="docutils literal"><span class="pre">4.2</span></code> or if read concern
majority is disabled.</p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.flowControlTargetLagSeconds">
<code class="descname">flowControlTargetLagSeconds</code><a class="headerlink" href="#param.flowControlTargetLagSeconds" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 10</p>
<p>The target maximum <a class="reference internal" href="command/replSetGetStatus.html#replSetGetStatus.optimes.lastCommittedOpTime" title="replSetGetStatus.optimes.lastCommittedOpTime"><code class="xref mongodb mongodb-data docutils literal"><span class="pre">majority</span> <span class="pre">committed</span></code></a> lag when running
with flow control. When flow control is enabled, the mechanism
attempts to keep the <a class="reference internal" href="command/replSetGetStatus.html#replSetGetStatus.optimes.lastCommittedOpTime" title="replSetGetStatus.optimes.lastCommittedOpTime"><code class="xref mongodb mongodb-data docutils literal"><span class="pre">majority</span> <span class="pre">committed</span></code></a> lag under
the specified seconds. The parameter has no effect if flow control
is disabled.</p>
<p>The specified value must be greater than 0.</p>
<p>In general, the default settings should suffice; however, if
modifying from the default value, decreasing, rather than
increasing, the value may prove to be more useful.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.flowControlWarnThresholdSeconds">
<code class="descname">flowControlWarnThresholdSeconds</code><a class="headerlink" href="#param.flowControlWarnThresholdSeconds" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 10</p>
<p>The amount of time to wait to log a warning once the flow control
mechanism detects the majority commit point has not moved.</p>
<p>The specified value must be greater than or equal to 0, with 0 to
disable warnings.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.oplogInitialFindMaxSeconds">
<code class="descname">oplogInitialFindMaxSeconds</code><a class="headerlink" href="#param.oplogInitialFindMaxSeconds" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 60</p>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Maximum time in seconds for a member of a <a class="reference internal" href="glossary.html#term-replica-set"><span class="xref std std-term">replica set</span></a> to wait
for the <a class="reference internal" href="command/find.html#dbcmd.find" title="find"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">find</span></code></a> command to finish during
<a class="reference internal" href="../core/replica-set-sync.html#replica-set-sync"><span class="std std-ref">data synchronization</span></a>.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.replWriterThreadCount">
<code class="descname">replWriterThreadCount</code><a class="headerlink" href="#param.replWriterThreadCount" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 16</p>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Number of threads to use to apply replicated operations in parallel.
Values can range from 1 to 256 inclusive. You can only set
<a class="reference internal" href="#param.replWriterThreadCount" title="replWriterThreadCount"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">replWriterThreadCount</span></code></a> at startup and cannot change this
setting with the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.rollbackTimeLimitSecs">
<code class="descname">rollbackTimeLimitSecs</code><a class="headerlink" href="#param.rollbackTimeLimitSecs" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Type</em>: 64-bit integer</p>
<p><em>Default</em>: 86400  (1 day)</p>
<p>Maximum age of data that can be rolled back. Negative values for
this parameter are not valid.</p>
<p>Starting in MongoDB 4.2+ and 4.0.13+, if the time between the end
of the to-be-rolledback instance’s oplog and the first operation
after the common point (the last point where the source node and the
to-be-rolledback node had the same data) exceeds this value, the
rollback will fail.</p>
<p>In MongoDB 4.0.0-4.0.12, if the time between the end of the to-be-rolledback
instance’s oplog and the common point (the last point where the
source node and the to-be-rolledback node had the same data) exceeds
this value, the rollback will fail.</p>
<p>To effectively have an unlimited rollback period, set the value to
<code class="docutils literal"><span class="pre">2147483647</span></code> which is the maximum value allowed and equivalent to
roughly 68 years.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.waitForSecondaryBeforeNoopWriteMS">
<code class="descname">waitForSecondaryBeforeNoopWriteMS</code><a class="headerlink" href="#param.waitForSecondaryBeforeNoopWriteMS" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 10</p>
<p>The length of time (in milliseconds) that a secondary must wait if
the <code class="docutils literal"><span class="pre">afterClusterTime</span></code> is greater than the last applied time from
the oplog. After the <code class="docutils literal"><span class="pre">waitForSecondaryBeforeNoopWriteMS</span></code> passes,
if the <code class="docutils literal"><span class="pre">afterClusterTime</span></code> is still greater than the last applied
time, the secondary makes a no-op write to advance the last applied
time.</p>
<p>The following example sets the
<a class="reference internal" href="#param.waitForSecondaryBeforeNoopWriteMS" title="waitForSecondaryBeforeNoopWriteMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">waitForSecondaryBeforeNoopWriteMS</span></code></a> to 20 milliseconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">waitForSecondaryBeforeNoopWriteMS</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
<p>During runtime, you can also set the parameter with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">waitForSecondaryBeforeNoopWriteMS</span><span class="o">:</span> <span class="mi">20</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.createRollbackDataFiles">
<code class="descname">createRollbackDataFiles</code><a class="headerlink" href="#param.createRollbackDataFiles" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Type</em>: boolean</p>
<p><em>Default</em>: true</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
<p>Flag that determines whether MongoDB creates <a class="reference internal" href="../core/replica-set-rollbacks.html#rollback-data-files"><span class="std std-ref">rollback files</span></a> that contains documents affected during a
rollback.</p>
<p>By default, <a class="reference internal" href="#param.createRollbackDataFiles" title="createRollbackDataFiles"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">createRollbackDataFiles</span></code></a> is <code class="docutils literal"><span class="pre">true</span></code> and
MongoDB creates the rollback files.</p>
<p>The following example sets <a class="reference internal" href="#param.createRollbackDataFiles" title="createRollbackDataFiles"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">createRollbackDataFiles</span></code></a>
to false so that the rollback files are not created:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">mongod</span> <span class="o">--</span><span class="nx">setParameter</span> <span class="nx">createRollbackDataFiles</span><span class="o">=</span><span class="kc">false</span>
</pre></div>
</div>
</div>
<p>During runtime, you can also set the parameter with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, createRollbackDataFiles: <span class="nb">false</span> <span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
<p>For more information, see <a class="reference internal" href="../core/replica-set-rollbacks.html#rollback-data-files"><span class="std std-ref">Collect Rollback Data</span></a>.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.enableElectionHandoff">
<code class="descname">enableElectionHandoff</code><a class="headerlink" href="#param.enableElectionHandoff" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.2.</span></p>
</div>
<p><em>Type</em>: boolean</p>
<p><em>Default</em>: true</p>
<p>A flag that can reduce the downtime after the primary steps down
from either the <a class="reference internal" href="method/rs.stepDown.html#rs.stepDown" title="rs.stepDown()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">rs.stepDown()</span></code></a> method or the
<a class="reference internal" href="command/replSetStepDown.html#dbcmd.replSetStepDown" title="replSetStepDown"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">replSetStepDown</span></code></a> command. Specifically, if true, when a
primary steps down after <a class="reference internal" href="method/rs.stepDown.html#rs.stepDown" title="rs.stepDown()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">rs.stepDown()</span></code></a> (or the
<a class="reference internal" href="command/replSetStepDown.html#dbcmd.replSetStepDown" title="replSetStepDown"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">replSetStepDown</span></code></a> command without the <code class="docutils literal"><span class="pre">force:</span> <span class="pre">true</span></code>),
it nominates an eligible secondary to call an election immediately.
If false, after the step down, secondaries can wait up to
<a class="reference internal" href="replica-configuration.html#rsconf.settings.electionTimeoutMillis" title="settings.electionTimeoutMillis"><code class="xref mongodb mongodb-rsconf docutils literal"><span class="pre">settings.electionTimeoutMillis</span></code></a> before calling an election.</p>
<p>An eligible secondary must be caught up with the stepped down
primary and have <a class="reference internal" href="replica-configuration.html#rsconf.members[n].priority" title="members[n].priority"><code class="xref mongodb mongodb-rsconf docutils literal"><span class="pre">priority</span></code></a> greater than 0. If
multiple secondary members meet this criteria, the stepped down
primary selects the eligible secondary with the highest
<a class="reference internal" href="replica-configuration.html#rsconf.members[n].priority" title="members[n].priority"><code class="xref mongodb mongodb-rsconf docutils literal"><span class="pre">priority</span></code></a>. If the more than one eligible
secondary members have the same <a class="reference internal" href="replica-configuration.html#rsconf.members[n].priority" title="members[n].priority"><code class="xref mongodb mongodb-rsconf docutils literal"><span class="pre">priority</span></code></a>, the
stepped down primary selects the secondary with the lowest
<a class="reference internal" href="replica-configuration.html#rsconf.members[n]._id" title="members[n]._id"><code class="xref mongodb mongodb-rsconf docutils literal"><span class="pre">_id</span></code></a>. The stepped down primary does not wait
for the effects of the handoff.</p>
<p>The parameter has no impact if the primary steps down for reasons
other than <a class="reference internal" href="method/rs.stepDown.html#rs.stepDown" title="rs.stepDown()"><code class="xref mongodb mongodb-method docutils literal"><span class="pre">rs.stepDown()</span></code></a> (or the
<a class="reference internal" href="command/replSetStepDown.html#dbcmd.replSetStepDown" title="replSetStepDown"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">replSetStepDown</span></code></a> command without the <code class="docutils literal"><span class="pre">force:</span> <span class="pre">true</span></code>).</p>
</dd></dl>

<dl class="parameter">
<dt id="param.replBatchLimitBytes">
<code class="descname">replBatchLimitBytes</code><a class="headerlink" href="#param.replBatchLimitBytes" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: 104857600 (100MB)</p>
<p>Sets the maximum oplog application batch size in bytes.</p>
<p>Values can range from 16777216 (16MB) to 104857600 (100MB) inclusive.</p>
<p>The following example sets <a class="reference internal" href="#param.replBatchLimitBytes" title="replBatchLimitBytes"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">replBatchLimitBytes</span></code></a>
to 64 MB so that the rollback files are not created:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">mongod</span> <span class="o">--</span><span class="nx">setParameter</span> <span class="nx">replBatchLimitBytes</span><span class="o">=</span><span class="mi">67108864</span>
</pre></div>
</div>
</div>
<p>During runtime, you can also set the parameter with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>db.adminCommand<span class="o">(</span> <span class="o">{</span> setParameter: <span class="m">1</span>, replBatchLimitBytes: <span class="m">64</span> * <span class="m">1024</span> * <span class="m">1024</span> <span class="o">}</span> <span class="o">)</span>
</pre></div>
</div>
</div>
<div class="versionadded">
<p><span class="versionmodified">New in version 4.0.10.</span></p>
</div>
</dd></dl>

</div>
<div class="section" id="sharding-parameters">
<h3>Sharding Parameters<a class="headerlink" href="#sharding-parameters" title="Permalink to this headline">¶</a></h3>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Starting in version 4.2, MongoDB removes the parameter
<code class="docutils literal"><span class="pre">AsyncRequestsSenderUseBaton</span></code> and always enables the performance
enhancement controlled by the parameter.</p>
</div>
<dl class="parameter">
<dt id="param.replMonitorMaxFailedChecks">
<code class="descname">replMonitorMaxFailedChecks</code><a class="headerlink" href="#param.replMonitorMaxFailedChecks" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Available in MongoDB 3.2 only</em></p>
<p>Type: integer</p>
<p>Default: 30</p>
<p>The number of times the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>
instance tries to reach the replica sets in the sharded cluster
(e.g. shard replica sets, config server replica set) to monitor the
replica set status and topology.</p>
<p>When the number of consecutive unsuccessful attempts exceeds this
parameter value, the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance
denotes the monitored replica set as unavailable. If the monitored
replica set is the config server replica set:</p>
<ul class="simple">
<li>For MongoDB 3.2.0-3.2.9, the monitoring <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance will become unusable and needs to be
restarted. See the <a class="reference external" href="https://docs.mongodb.com/v3.2/tutorial/troubleshoot-sharded-clusters/#a-config-server-replica-set-member-become-unavailable">v3.2 troubleshooting guide</a>
for more details.</li>
<li>For MongoDB 3.2.10 and later 3.2-series, see also
<a class="reference internal" href="#param.timeOutMonitoringReplicaSets" title="timeOutMonitoringReplicaSets"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">timeOutMonitoringReplicaSets</span></code></a>.</li>
</ul>
</dd></dl>

<dl class="parameter">
<dt id="param.timeOutMonitoringReplicaSets">
<code class="descname">timeOutMonitoringReplicaSets</code><a class="headerlink" href="#param.timeOutMonitoringReplicaSets" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Available in MongoDB 3.2.10 and later 3.2-series only</em></p>
<p>Type: integer</p>
<p>Default: false</p>
<p>The flag that determines whether the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance should stop its attempt to reach the
monitored replica set after unsuccessfully trying
<a class="reference internal" href="#param.replMonitorMaxFailedChecks" title="replMonitorMaxFailedChecks"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">replMonitorMaxFailedChecks</span></code></a> number of times.</p>
<p>If the monitored replica set is the config server replica set and
<a class="reference internal" href="#param.timeOutMonitoringReplicaSets" title="timeOutMonitoringReplicaSets"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">timeOutMonitoringReplicaSets</span></code></a> is set to <code class="docutils literal"><span class="pre">true</span></code>, you
must restart <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> if the
<a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> or <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance cannot reach any of
the config servers for the specified number of times. See the
<a class="reference external" href="https://docs.mongodb.com/v3.2/tutorial/troubleshoot-sharded-clusters/#a-config-server-replica-set-member-become-unavailable">v3.2 troubleshooting guide</a>
for more details.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolHostTimeoutMS">
<code class="descname">ShardingTaskExecutorPoolHostTimeoutMS</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolHostTimeoutMS" title="Permalink to this definition">¶</a></dt>
<dd><p>Type: integer</p>
<p>Default: 300000 (i.e. 5 minutes)</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Maximum time that <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> goes without communication to a
host before <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> drops all connections to the host.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<p>If set, <a class="reference internal" href="#param.ShardingTaskExecutorPoolHostTimeoutMS" title="ShardingTaskExecutorPoolHostTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolHostTimeoutMS</span></code></a> should be
greater than the sum of
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="ShardingTaskExecutorPoolRefreshRequirementMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshRequirementMS</span></code></a> and
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="ShardingTaskExecutorPoolRefreshTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshTimeoutMS</span></code></a>. Otherwise,
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> adjusts the value of
<a class="reference internal" href="#param.ShardingTaskExecutorPoolHostTimeoutMS" title="ShardingTaskExecutorPoolHostTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolHostTimeoutMS</span></code></a> to be greater than the
sum.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolHostTimeoutMS</span><span class="o">=</span><span class="m">120000</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolMaxConnecting">
<code class="descname">ShardingTaskExecutorPoolMaxConnecting</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolMaxConnecting" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Type: integer</p>
<p>Default: 2</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Maximum number of simultaneous initiating connections (including
pending connections in setup/refresh state) each TaskExecutor
connection pool can have to a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance. You can
set this parameter to control the rate at which <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>
adds connections to a <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance.</p>
<p>If set, <a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxConnecting" title="ShardingTaskExecutorPoolMaxConnecting"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxConnecting</span></code></a> should be
less than or equal to <a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxSize" title="ShardingTaskExecutorPoolMaxSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxSize</span></code></a>.
If it is greater, <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> ignores the
<a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxConnecting" title="ShardingTaskExecutorPoolMaxConnecting"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxConnecting</span></code></a> value.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolMaxConnecting</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolMaxSize">
<code class="descname">ShardingTaskExecutorPoolMaxSize</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolMaxSize" title="Permalink to this definition">¶</a></dt>
<dd><p>Type: integer</p>
<p>Default: 2<sup>64</sup> - 1</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Maximum number of outbound connections each TaskExecutor connection
pool can open to any given <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance. The maximum
possible connections to any given host across all TaskExecutor pools
is:</p>
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<div class="copyable-code-block highlight-none"><div class="highlight"><pre><span></span>ShardingTaskExecutorPoolMaxSize * taskExecutorPoolSize
</pre></div>
</div>
</div>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolMaxSize</span><span class="o">=</span><span class="m">4</span>
</pre></div>
</div>
</div>
<p><a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> can have up to <code class="docutils literal"><span class="pre">n</span></code> TaskExecutor connection
pools, where <code class="docutils literal"><span class="pre">n</span></code> is the number of cores. See
<a class="reference internal" href="#param.taskExecutorPoolSize" title="taskExecutorPoolSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">taskExecutorPoolSize</span></code></a>.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.ShardingTaskExecutorPoolMinSize" title="ShardingTaskExecutorPoolMinSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMinSize</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolMinSize">
<code class="descname">ShardingTaskExecutorPoolMinSize</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolMinSize" title="Permalink to this definition">¶</a></dt>
<dd><p>Type: integer</p>
<p>Default: 1</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Minimum number of outbound connections each TaskExecutor connection
pool can open to any given <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance.</p>
<p><code class="docutils literal"><span class="pre">ShardingTaskExecutorPoolMinSize</span></code> connections are created the
first time a connection to a new host is requested from the pool.
While the pool is idle, the pool maintains this number of
connections until <a class="reference internal" href="#param.ShardingTaskExecutorPoolHostTimeoutMS" title="ShardingTaskExecutorPoolHostTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolHostTimeoutMS</span></code></a>
milliseconds pass without any application using that pool.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolMinSize</span><span class="o">=</span><span class="m">2</span>
</pre></div>
</div>
</div>
<p><a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> can have up to <code class="docutils literal"><span class="pre">n</span></code> TaskExecutor connection
pools, where <code class="docutils literal"><span class="pre">n</span></code> is the number of cores. See
<a class="reference internal" href="#param.taskExecutorPoolSize" title="taskExecutorPoolSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">taskExecutorPoolSize</span></code></a>.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxSize" title="ShardingTaskExecutorPoolMaxSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxSize</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolRefreshRequirementMS">
<code class="descname">ShardingTaskExecutorPoolRefreshRequirementMS</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="Permalink to this definition">¶</a></dt>
<dd><p>Type: integer</p>
<p>Default: 60000 (1 minute)</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Maximum time the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> waits before attempting to
heartbeat a resting connection in the pool.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<p>If set, <a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="ShardingTaskExecutorPoolRefreshRequirementMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshRequirementMS</span></code></a> should be
greater than <a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="ShardingTaskExecutorPoolRefreshTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshTimeoutMS</span></code></a>.
Otherwise, <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> adjusts the value of
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="ShardingTaskExecutorPoolRefreshTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshTimeoutMS</span></code></a> to be less than
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="ShardingTaskExecutorPoolRefreshRequirementMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshRequirementMS</span></code></a>.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolRefreshRequirementMS</span><span class="o">=</span><span class="m">90000</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolRefreshTimeoutMS">
<code class="descname">ShardingTaskExecutorPoolRefreshTimeoutMS</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="Permalink to this definition">¶</a></dt>
<dd><p>Type: integer</p>
<p>Default: 20000 (20 seconds)</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>Maximum time the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> waits for a heartbeat before
timing out the heartbeat.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<p>If set, <a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="ShardingTaskExecutorPoolRefreshTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshTimeoutMS</span></code></a> should be
less than <a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="ShardingTaskExecutorPoolRefreshRequirementMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshRequirementMS</span></code></a>.
Otherwise, <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> adjusts the value of
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshTimeoutMS" title="ShardingTaskExecutorPoolRefreshTimeoutMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshTimeoutMS</span></code></a> to be less than
<a class="reference internal" href="#param.ShardingTaskExecutorPoolRefreshRequirementMS" title="ShardingTaskExecutorPoolRefreshRequirementMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolRefreshRequirementMS</span></code></a>.</p>
<div class="button-code-block">
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</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">ShardingTaskExecutorPoolRefreshTimeoutMS</span><span class="o">=</span><span class="m">30000</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.ShardingTaskExecutorPoolReplicaSetMatching">
<code class="descname">ShardingTaskExecutorPoolReplicaSetMatching</code><a class="headerlink" href="#param.ShardingTaskExecutorPoolReplicaSetMatching" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.2.</span></p>
</div>
<p>Type: string</p>
<p>Default: “matchPrimaryNode”</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>The policy that determines the minimum size limit of the
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s connection pools to the sharded
cluster’s replica set secondaries.</p>
<p>Available values are:</p>
<table border="1" class="colwidths-given docutils">
<colgroup>
<col width="15%" />
<col width="85%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Matching Policy</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal"><span class="pre">&quot;matchPrimaryNode&quot;</span></code> (Default)</td>
<td><p class="first">For each replica set in the sharded cluster (i.e. shard
replica set and config servers), the minimum size limit of
the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s connection pool to each
secondary of that replica set is equal to the size of its
connection pool to the primary.</p>
<p class="last">In case of primary stepdown, <code class="docutils literal"><span class="pre">matchPrimaryNode</span></code> ensures
that any secondary that becomes the primary can handle the
current level of primary reads and writes.</p>
</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">&quot;matchBusiestNode&quot;</span></code></td>
<td><p class="first">For each replica set in the sharded cluster (i.e. shard
replica set and config servers), the minimum size limit of
the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s connection pool to each
member of that replica set is equal to the largest among
the active connections counts to the primary and each
secondary members.</p>
<p class="last">With <code class="docutils literal"><span class="pre">&quot;matchBusiestNode&quot;</span></code>, <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> maintains
enough connections to each secondary to handle the current
level of primary and secondary reads and writes. The number
of connections to maintain in the pool decreases as the
number of active connections decreases.</p>
</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">&quot;disabled&quot;</span></code></td>
<td>For each replica set in the sharded cluster (i.e. shard
replica set and config servers), the minimum number of
connections in the <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> instance’s
connection pool to each secondary is equal to the
<a class="reference internal" href="#param.ShardingTaskExecutorPoolMinSize" title="ShardingTaskExecutorPoolMinSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMinSize</span></code></a>.</td>
</tr>
</tbody>
</table>
<p>The following example sets the
<a class="reference internal" href="#param.ShardingTaskExecutorPoolReplicaSetMatching" title="ShardingTaskExecutorPoolReplicaSetMatching"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolReplicaSetMatching</span></code></a> to
<code class="docutils literal"><span class="pre">&quot;matchBusiestNode&quot;</span></code> during startup:</p>
<div class="button-code-block">
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">ShardingTaskExecutorPoolReplicaSetMatching</span><span class="o">=</span><span class="s2">&quot;matchBusiestNode&quot;</span>
</pre></div>
</div>
</div>
<p>During runtime, you can also set the parameter with the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
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</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span>  <span class="nx">ShardingTaskExecutorPoolReplicaSetMatching</span><span class="o">:</span> <span class="s2">&quot;matchBusiestNode&quot;</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.taskExecutorPoolSize">
<code class="descname">taskExecutorPoolSize</code><a class="headerlink" href="#param.taskExecutorPoolSize" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionchanged">
<p><span class="versionmodified">Changed in version 4.0.</span></p>
</div>
<p>Type: integer</p>
<p>Default: 1</p>
<p>Available for <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a> only.</p>
<p>The number of Task Executor connection pools to use for a given
<a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>If the parameter value is <code class="docutils literal"><span class="pre">0</span></code> or less, the number of Task Executor
connection pools is the number of cores with the following
exceptions:</p>
<ul class="simple">
<li>If the number of cores is less than 4, the number of Task Executor
connection pools is 4.</li>
<li>If the number of cores is greater than 64, the number of Task
Executor connection pools is 64.</li>
</ul>
<p>Starting in MongoDB 4.0, the default value of
<a class="reference internal" href="#param.taskExecutorPoolSize" title="taskExecutorPoolSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">taskExecutorPoolSize</span></code></a> is <code class="docutils literal"><span class="pre">1</span></code>:</p>
<ul class="simple">
<li>In MongoDB 4.0 deployment, you can set
<a class="reference internal" href="#param.taskExecutorPoolSize" title="taskExecutorPoolSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">taskExecutorPoolSize</span></code></a> to <code class="docutils literal"><span class="pre">0</span></code> and, on Linux, set
<a class="reference external" href="https://docs.mongodb.com/v4.0/reference/parameters/#param.AsyncRequestsSenderUseBaton">AsyncRequestsSenderUseBaton</a> to
<code class="docutils literal"><span class="pre">false</span></code> for the previous behavior.</li>
<li>In MongoDB 4.2+ deployment, MongoDB removes the
<code class="docutils literal"><span class="pre">AsyncRequestsSenderUseBaton</span></code> parameter and always enables the
performance enhancement controlled by the parameter.</li>
</ul>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
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<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongos --setParameter <span class="nv">taskExecutorPoolSize</span><span class="o">=</span><span class="m">6</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<ul class="last simple">
<li><a class="reference internal" href="#param.ShardingTaskExecutorPoolMaxSize" title="ShardingTaskExecutorPoolMaxSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMaxSize</span></code></a></li>
<li><a class="reference internal" href="#param.ShardingTaskExecutorPoolMinSize" title="ShardingTaskExecutorPoolMinSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">ShardingTaskExecutorPoolMinSize</span></code></a></li>
</ul>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.migrateCloneInsertionBatchDelayMS">
<code class="descname">migrateCloneInsertionBatchDelayMS</code><a class="headerlink" href="#param.migrateCloneInsertionBatchDelayMS" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.5: </span>The parameter is also available starting in 3.4.18 and 3.6.10</p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Type: Non-negative integer</p>
<p>Default: 0</p>
<p>Time in milliseconds to wait between batches of insertions during
cloning step of the migration process. This wait is in addition to
the <code class="docutils literal"><span class="pre">secondaryThrottle</span></code>.</p>
<p>The default value of <code class="docutils literal"><span class="pre">0</span></code> indicates no additional wait.</p>
<p>The following sets the <a class="reference internal" href="#param.migrateCloneInsertionBatchDelayMS" title="migrateCloneInsertionBatchDelayMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">migrateCloneInsertionBatchDelayMS</span></code></a> to 200
milliseconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">migrateCloneInsertionBatchDelayMS</span><span class="o">=</span><span class="m">200</span>
</pre></div>
</div>
</div>
<p>The parameter may also be set using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">migrateCloneInsertionBatchDelayMS</span><span class="o">:</span> <span class="mi">200</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.migrateCloneInsertionBatchSize">
<code class="descname">migrateCloneInsertionBatchSize</code><a class="headerlink" href="#param.migrateCloneInsertionBatchSize" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.5: </span>The parameter is also available starting in 3.4.18 and 3.6.10</p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Type: Non-negative integer</p>
<p>Default: 0</p>
<p>The maximum number of documents to insert in a single batch during
the cloning step of the migration process.</p>
<p>The default value of <code class="docutils literal"><span class="pre">0</span></code> indicates no maximum number of documents
per batch. However, in practice, this results in batches that
contain up to 16 MB of documents.</p>
<p>The following sets the <a class="reference internal" href="#param.migrateCloneInsertionBatchSize" title="migrateCloneInsertionBatchSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">migrateCloneInsertionBatchSize</span></code></a> to 100
documents:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">migrateCloneInsertionBatchSize</span><span class="o">=</span><span class="m">100</span>
</pre></div>
</div>
</div>
<p>The parameter may also be set using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">migrateCloneInsertionBatchSize</span><span class="o">:</span> <span class="mi">100</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.orphanCleanupDelaySecs">
<code class="descname">orphanCleanupDelaySecs</code><a class="headerlink" href="#param.orphanCleanupDelaySecs" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p>Default: 900 (15 minutes)</p>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Minimum delay before a migrated <a class="reference internal" href="glossary.html#term-chunk"><span class="xref std std-term">chunk</span></a> is deleted from the source
shard.</p>
<p>Before deleting the chunk during chunk migration, MongoDB waits for
<a class="reference internal" href="#param.orphanCleanupDelaySecs" title="orphanCleanupDelaySecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">orphanCleanupDelaySecs</span></code></a> or for in-progress queries involving
the chunk to complete on the shard primary, whichever is longer.</p>
<p>However, because the shard primary has no knowledge of in-progress queries
run on the shard secondaries, queries that use the chunk but are run on
secondaries may see documents disappear if these queries take longer than
the time to complete the shard primary queries and the
<a class="reference internal" href="#param.orphanCleanupDelaySecs" title="orphanCleanupDelaySecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">orphanCleanupDelaySecs</span></code></a>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">This behavior only affects in-progress queries that start before the
chunk migration. Queries that start after the chunk migration starts
will not use the migrating chunk.</p>
</div>
<p>If a shard has storage constraints, consider reducing this value
temporarily. If running queries that exceed 15 minutes on shard
secondaries, consider increasing this value.</p>
<p>The following sets the <a class="reference internal" href="#param.orphanCleanupDelaySecs" title="orphanCleanupDelaySecs"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">orphanCleanupDelaySecs</span></code></a> to 20 minutes:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">orphanCleanupDelaySecs</span><span class="o">=</span><span class="m">1200</span>
</pre></div>
</div>
</div>
<p>This may also be set using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">orphanCleanupDelaySecs</span><span class="o">:</span> <span class="mi">1200</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.rangeDeleterBatchDelayMS">
<code class="descname">rangeDeleterBatchDelayMS</code><a class="headerlink" href="#param.rangeDeleterBatchDelayMS" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.1: </span>The parameter is also available starting in 3.4.17 and 3.6.7.</p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Type: Non-negative integer</p>
<p>Default: 20</p>
<p>The amount of time in milliseconds to wait before the next batch of
deletion during the cleanup stage of <a class="reference internal" href="../core/sharding-balancer-administration.html#chunk-migration-procedure"><span class="std std-ref">chunk migration</span></a> (or the <a class="reference internal" href="command/cleanupOrphaned.html#dbcmd.cleanupOrphaned" title="cleanupOrphaned"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">cleanupOrphaned</span></code></a>
command).</p>
<p>In MongoDB 3.4, consider whether <a class="reference internal" href="../core/sharding-balancer-administration.html#chunk-migration-replication"><span class="std std-ref">_secondaryThrottle</span></a> is set before modifying the
<a class="reference internal" href="#param.rangeDeleterBatchDelayMS" title="rangeDeleterBatchDelayMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">rangeDeleterBatchDelayMS</span></code></a>. In MongoDB 3.4, the
<a class="reference internal" href="../core/sharding-balancer-administration.html#chunk-migration-replication"><span class="std std-ref">_secondaryThrottle replication delay</span></a> occurs after each document deletion
instead of after the batch deletion.</p>
<p>In MongoDB 3.6+, the <a class="reference internal" href="../core/sharding-balancer-administration.html#chunk-migration-replication"><span class="std std-ref">_secondaryThrottle replication delay</span></a> occurs after each batch deletion.</p>
<p>The following sets the <a class="reference internal" href="#param.rangeDeleterBatchDelayMS" title="rangeDeleterBatchDelayMS"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">rangeDeleterBatchDelayMS</span></code></a> to 200
milliseconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">rangeDeleterBatchDelayMS</span><span class="o">=</span><span class="m">200</span>
</pre></div>
</div>
</div>
<p>The parameter may also be set using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">rangeDeleterBatchDelayMS</span><span class="o">:</span> <span class="mi">200</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.rangeDeleterBatchSize">
<code class="descname">rangeDeleterBatchSize</code><a class="headerlink" href="#param.rangeDeleterBatchSize" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.5: </span>The parameter is also available starting in 3.4.19 and 3.6.10</p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Type: Non-negative integer</p>
<p>Default: 0</p>
<p>The maximum number of documents in each batch to delete during the
cleanup stage of <a class="reference internal" href="../core/sharding-balancer-administration.html#chunk-migration-procedure"><span class="std std-ref">chunk migration</span></a>
(or the <a class="reference internal" href="command/cleanupOrphaned.html#dbcmd.cleanupOrphaned" title="cleanupOrphaned"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">cleanupOrphaned</span></code></a> command).</p>
<p>The default value of <code class="docutils literal"><span class="pre">0</span></code> indicates that the system chooses an
appropriate value, generally 128 documents.</p>
<p>The following sets the <a class="reference internal" href="#param.rangeDeleterBatchSize" title="rangeDeleterBatchSize"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">rangeDeleterBatchSize</span></code></a> to 100
documents:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">rangeDeleterBatchSize</span><span class="o">=</span><span class="m">100</span>
</pre></div>
</div>
</div>
<p>The parameter may also be set using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a>
command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">rangeDeleterBatchSize</span><span class="o">:</span> <span class="mi">100</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.skipShardingConfigurationChecks">
<code class="descname">skipShardingConfigurationChecks</code><a class="headerlink" href="#param.skipShardingConfigurationChecks" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.3.</span></p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Type: boolean</p>
<p>Default: false</p>
<p>When <code class="docutils literal"><span class="pre">true</span></code>, allows for starting a shard member or config server
member as a standalone for maintenance operations. This parameter is
mutually exclusive with the <a class="reference internal" href="program/mongod.html#cmdoption-mongod-configsvr"><code class="xref std std-option docutils literal"><span class="pre">--configsvr</span></code></a> or <a class="reference internal" href="program/mongod.html#cmdoption-mongod-shardsvr"><code class="xref std std-option docutils literal"><span class="pre">--shardsvr</span></code></a> options.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">skipShardingConfigurationChecks</span><span class="o">=</span><span class="nb">true</span>
</pre></div>
</div>
</div>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">Once maintenance has completed, remove the
<a class="reference internal" href="#param.skipShardingConfigurationChecks" title="skipShardingConfigurationChecks"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">skipShardingConfigurationChecks</span></code></a> parameter when
restarting the <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>.</p>
</div>
<p>The parameter is also available for MongoDB versions:</p>
<ul class="simple">
<li>MongoDB 3.2.19+</li>
<li>MongoDB 3.4.11+</li>
</ul>
</dd></dl>

</div>
<div class="section" id="storage-parameters">
<h3>Storage Parameters<a class="headerlink" href="#storage-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.journalCommitInterval">
<code class="descname">journalCommitInterval</code><a class="headerlink" href="#param.journalCommitInterval" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Specify an integer between <code class="docutils literal"><span class="pre">1</span></code> and <code class="docutils literal"><span class="pre">500</span></code> signifying the number
of milliseconds (ms) between journal commits.</p>
<p>Consider the following example which sets the
<a class="reference internal" href="#param.journalCommitInterval" title="journalCommitInterval"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">journalCommitInterval</span></code></a> to <code class="docutils literal"><span class="pre">200</span></code> ms:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">journalCommitInterval</span><span class="o">:</span> <span class="mi">200</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="configuration-options.html#storage.journal.commitIntervalMs" title="storage.journal.commitIntervalMs"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.journal.commitIntervalMs</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.syncdelay">
<code class="descname">syncdelay</code><a class="headerlink" href="#param.syncdelay" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Specify the interval in seconds between <a class="reference internal" href="glossary.html#term-fsync"><span class="xref std std-term">fsync</span></a> operations
where <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> flushes its working memory to disk. By
default, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> flushes memory to disk every 60
seconds. In almost every situation you should not set this value
and use the default setting.</p>
<p>Consider the following example which sets the <code class="docutils literal"><span class="pre">syncdelay</span></code> to
<code class="docutils literal"><span class="pre">60</span></code> seconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">syncdelay</span><span class="o">:</span> <span class="mi">60</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<ul class="last simple">
<li><a class="reference internal" href="#param.journalCommitInterval" title="journalCommitInterval"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">journalCommitInterval</span></code></a></li>
<li><a class="reference internal" href="configuration-options.html#storage.syncPeriodSecs" title="storage.syncPeriodSecs"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.syncPeriodSecs</span></code></a></li>
</ul>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.honorSystemUmask">
<code class="descname">honorSystemUmask</code><a class="headerlink" href="#param.honorSystemUmask" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
<p><em>Default</em>: <code class="docutils literal"><span class="pre">false</span></code></p>
<p>If <a class="reference internal" href="#param.honorSystemUmask" title="honorSystemUmask"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">honorSystemUmask</span></code></a> is set to <code class="docutils literal"><span class="pre">true</span></code>, new files
created by MongoDB have permissions in accordance with the
user’s <code class="docutils literal"><span class="pre">umask</span></code> settings.</p>
<p>If <a class="reference internal" href="#param.honorSystemUmask" title="honorSystemUmask"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">honorSystemUmask</span></code></a> is set to <code class="docutils literal"><span class="pre">false</span></code>, new files
created by MongoDB have permissions set to <code class="docutils literal"><span class="pre">600</span></code>, which gives
read and write permissions only to the owner. New directories have
permissions set to <code class="docutils literal"><span class="pre">700</span></code>.</p>
<p>You can only set this parameter during start-up and cannot change
this setting using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">honorSystemUmask</span><span class="o">=</span><span class="nb">true</span>
</pre></div>
</div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last"><a class="reference internal" href="#param.honorSystemUmask" title="honorSystemUmask"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">honorSystemUmask</span></code></a> is not available on Windows systems.</p>
</div>
</dd></dl>

</div>
<div class="section" id="wiredtiger-parameters">
<h3>WiredTiger Parameters<a class="headerlink" href="#wiredtiger-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.wiredTigerMaxCacheOverflowSizeGB">
<code class="descname">wiredTigerMaxCacheOverflowSizeGB</code><a class="headerlink" href="#param.wiredTigerMaxCacheOverflowSizeGB" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Available starting in MongoDB 4.2.1 (and 4.0.12)</em></p>
<p><em>Default</em>: 0 (No specified maximum)</p>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Specify the maximum size (in GB) for the “lookaside (or cache
overflow) table” file <code class="file docutils literal"><span class="pre">WiredTigerLAS.wt</span></code>.</p>
<p>The parameter can accept the following values:</p>
<table border="1" class="colwidths-given docutils">
<colgroup>
<col width="20%" />
<col width="80%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Value</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal"><span class="pre">0</span></code></td>
<td>The default value. If set to <code class="docutils literal"><span class="pre">0</span></code>, the file size is
unbounded.</td>
</tr>
<tr class="row-odd"><td>number &gt;= 0.1</td>
<td>The maximum size (in GB). If the <code class="file docutils literal"><span class="pre">WiredTigerLAS.wt</span></code>
file exceeds this size, <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> exits with a
fatal assertion. You can clear the <code class="file docutils literal"><span class="pre">WiredTigerLAS.wt</span></code>
file and restart <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a>.</td>
</tr>
</tbody>
</table>
<p>You can only set this parameter during runtime using the
<a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> database command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">wiredTigerMaxCacheOverflowSizeGB</span><span class="o">:</span> <span class="mi">100</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>To set the maximum size during start up, use the
<a class="reference internal" href="configuration-options.html#storage.wiredTiger.engineConfig.maxCacheOverflowFileSizeGB" title="storage.wiredTiger.engineConfig.maxCacheOverflowFileSizeGB"><code class="xref mongodb mongodb-setting docutils literal"><span class="pre">storage.wiredTiger.engineConfig.maxCacheOverflowFileSizeGB</span></code></a>
instead.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.wiredTigerConcurrentReadTransactions">
<code class="descname">wiredTigerConcurrentReadTransactions</code><a class="headerlink" href="#param.wiredTigerConcurrentReadTransactions" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Available for the WiredTiger storage engine only.</p>
<p>Specify the maximum number of concurrent read transactions allowed
into the WiredTiger storage engine.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">wiredTigerConcurrentReadTransactions</span><span class="o">:</span> <span class="o">&lt;</span><span class="nx">num</span><span class="o">&gt;</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="command/serverStatus.html#serverstatus.wiredTiger.concurrentTransactions" title="wiredTiger.concurrentTransactions"><code class="xref mongodb mongodb-serverstatus docutils literal"><span class="pre">wiredTiger.concurrentTransactions</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.wiredTigerConcurrentWriteTransactions">
<code class="descname">wiredTigerConcurrentWriteTransactions</code><a class="headerlink" href="#param.wiredTigerConcurrentWriteTransactions" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Available for the WiredTiger storage engine only.</p>
<p>Specify the maximum number of concurrent write transactions allowed
into the WiredTiger storage engine.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">wiredTigerConcurrentWriteTransactions</span><span class="o">:</span> <span class="o">&lt;</span><span class="nx">num</span><span class="o">&gt;</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="command/serverStatus.html#serverstatus.wiredTiger.concurrentTransactions" title="wiredTiger.concurrentTransactions"><code class="xref mongodb mongodb-serverstatus docutils literal"><span class="pre">wiredTiger.concurrentTransactions</span></code></a></p>
</div>
</dd></dl>

<dl class="parameter">
<dt id="param.wiredTigerEngineRuntimeConfig">
<code class="descname">wiredTigerEngineRuntimeConfig</code><a class="headerlink" href="#param.wiredTigerEngineRuntimeConfig" title="Permalink to this definition">¶</a></dt>
<dd><p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p>Specify <code class="docutils literal"><span class="pre">wiredTiger</span></code> storage engine configuration options for a
running <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> instance. You can <em>only</em> set this
parameter using the <a class="reference internal" href="command/setParameter.html#dbcmd.setParameter" title="setParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">setParameter</span></code></a> command and <em>not</em>
using the command line or configuration file option.</p>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">Avoid modifying the <a class="reference internal" href="#param.wiredTigerEngineRuntimeConfig" title="wiredTigerEngineRuntimeConfig"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">wiredTigerEngineRuntimeConfig</span></code></a>
unless under the direction from MongoDB engineers as this setting has
major implication across both WiredTiger and MongoDB.</p>
</div>
<p>Consider the following operation prototype:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">({</span>
   <span class="s2">&quot;setParameter&quot;</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span>
   <span class="s2">&quot;wiredTigerEngineRuntimeConfig&quot;</span><span class="o">:</span> <span class="s2">&quot;&lt;option&gt;=&lt;setting&gt;,&lt;option&gt;=&lt;setting&gt;&quot;</span>
<span class="p">})</span>
</pre></div>
</div>
</div>
<p>See the WiredTiger documentation for all available <a class="reference external" href="https://source.wiredtiger.com/mongodb-3.4/struct_w_t___c_o_n_n_e_c_t_i_o_n.html#">WiredTiger
configuration options</a>.</p>
</dd></dl>

</div>
<div class="section" id="auditing-parameters">
<h3>Auditing Parameters<a class="headerlink" href="#auditing-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.auditAuthorizationSuccess">
<code class="descname">auditAuthorizationSuccess</code><a class="headerlink" href="#param.auditAuthorizationSuccess" title="Permalink to this definition">¶</a></dt>
<dd><p><em>Default</em>: <code class="docutils literal"><span class="pre">false</span></code></p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Available only in <a class="reference external" href="http://www.mongodb.com/products/mongodb-enterprise-advanced?jmp=docs">MongoDB Enterprise</a>
and <a class="reference external" href="https://cloud.mongodb.com/user#/atlas/login">MongoDB Atlas</a>.</p>
</div>
<p>Available for both <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> and <a class="reference internal" href="program/mongos.html#bin.mongos" title="bin.mongos"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongos</span></code></a>.</p>
<p>Enables the <a class="reference internal" href="../core/auditing.html"><span class="doc">auditing</span></a> of authorization
successes for the <a class="reference internal" href="audit-message.html#audit-action-details-results"><span class="std std-ref">authCheck</span></a>
action.</p>
<p>When <a class="reference internal" href="#param.auditAuthorizationSuccess" title="auditAuthorizationSuccess"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">auditAuthorizationSuccess</span></code></a> is <code class="docutils literal"><span class="pre">false</span></code>, the
<a class="reference internal" href="../core/auditing.html"><span class="doc">audit system</span></a> only logs the authorization
failures for <code class="docutils literal"><span class="pre">authCheck</span></code>.</p>
<p>To enable the audit of authorization successes, issue the following
command:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">auditAuthorizationSuccess</span><span class="o">:</span> <span class="kc">true</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>Enabling <a class="reference internal" href="#param.auditAuthorizationSuccess" title="auditAuthorizationSuccess"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">auditAuthorizationSuccess</span></code></a> degrades performance
more than logging only the authorization failures.</p>
</dd></dl>

<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="command/getParameter.html#dbcmd.getParameter" title="getParameter"><code class="xref mongodb mongodb-dbcommand docutils literal"><span class="pre">getParameter</span></code></a></p>
</div>
</div>
<div class="section" id="transaction-parameters">
<h3>Transaction Parameters<a class="headerlink" href="#transaction-parameters" title="Permalink to this headline">¶</a></h3>
<dl class="parameter">
<dt id="param.transactionLifetimeLimitSeconds">
<code class="descname">transactionLifetimeLimitSeconds</code><a class="headerlink" href="#param.transactionLifetimeLimitSeconds" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Default</em>: 60</p>
<p>Specifies the lifetime of <a class="reference internal" href="../core/transactions.html"><span class="doc">multi-document transactions</span></a>. Transactions that exceeds this limit are
considered expired and will be aborted by a periodic cleanup
process. The cleanup process runs every
<a class="reference internal" href="#param.transactionLifetimeLimitSeconds" title="transactionLifetimeLimitSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">transactionLifetimeLimitSeconds</span></code></a>/2 seconds or at least
once per every 60 seconds.</p>
<p>The cleanup process helps relieve storage cache pressure.</p>
<p>The minimum value for transactionLifetimeLimitSeconds is <code class="docutils literal"><span class="pre">1</span></code>
second.</p>
<p>The following sets the
<a class="reference internal" href="#param.transactionLifetimeLimitSeconds" title="transactionLifetimeLimitSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">transactionLifetimeLimitSeconds</span></code></a> to <code class="docutils literal"><span class="pre">30</span></code>
seconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">transactionLifetimeLimitSeconds</span><span class="o">:</span> <span class="mi">30</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>You can also set parameter <a class="reference internal" href="#param.transactionLifetimeLimitSeconds" title="transactionLifetimeLimitSeconds"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">transactionLifetimeLimitSeconds</span></code></a> at
startup time.</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="s2">&quot;transactionLifetimeLimitSeconds=30&quot;</span>
</pre></div>
</div>
</div>
<p>To set the parameter for a sharded cluster, the parameter must be
modified for all shard replica set members.</p>
</dd></dl>

<dl class="parameter">
<dt id="param.maxTransactionLockRequestTimeoutMillis">
<code class="descname">maxTransactionLockRequestTimeoutMillis</code><a class="headerlink" href="#param.maxTransactionLockRequestTimeoutMillis" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
<p><span class="versionmodified">New in version 4.0.</span></p>
</div>
<p>Available for <a class="reference internal" href="program/mongod.html#bin.mongod" title="bin.mongod"><code class="xref mongodb mongodb-binary docutils literal"><span class="pre">mongod</span></code></a> only.</p>
<p><em>Type</em>: integer</p>
<p><em>Default</em>: 5</p>
<p>The maximum amount of time in milliseconds that <a class="reference internal" href="../core/transactions.html"><span class="doc">multi-document
transactions</span></a> should wait to acquire locks
required by the operations in the transaction.</p>
<p>If the transaction cannot acquire the locks after waiting
<a class="reference internal" href="#param.maxTransactionLockRequestTimeoutMillis" title="maxTransactionLockRequestTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxTransactionLockRequestTimeoutMillis</span></code></a>, the transaction
aborts.</p>
<p>By default, <a class="reference internal" href="../core/transactions.html"><span class="doc">multi-document transactions</span></a>
wait <code class="docutils literal"><span class="pre">5</span></code> milliseconds. That is, if the transaction cannot acquire
the locks within <code class="docutils literal"><span class="pre">5</span></code> milliseconds, the transaction aborts. If an
operation provides a greater timeout in a lock request,
<a class="reference internal" href="#param.maxTransactionLockRequestTimeoutMillis" title="maxTransactionLockRequestTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxTransactionLockRequestTimeoutMillis</span></code></a> overrides the
operation-specific timeout.</p>
<p>You can set <a class="reference internal" href="#param.maxTransactionLockRequestTimeoutMillis" title="maxTransactionLockRequestTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxTransactionLockRequestTimeoutMillis</span></code></a> to:</p>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">0</span></code> such that if the transaction cannot acquire the required
locks immediately, the transaction aborts.</li>
<li>A number greater than <code class="docutils literal"><span class="pre">0</span></code> to wait the specified time to acquire
the required locks. This can help obviate transaction aborts on
momentary concurrent lock acquisitions, like fast-running metadata
operations. However, this could possibly delay the abort of
deadlocked transaction operations.</li>
<li><code class="docutils literal"><span class="pre">-1</span></code> to use the operation specific timeout.</li>
</ul>
<p>The following sets the
<a class="reference internal" href="#param.maxTransactionLockRequestTimeoutMillis" title="maxTransactionLockRequestTimeoutMillis"><code class="xref mongodb mongodb-parameter docutils literal"><span class="pre">maxTransactionLockRequestTimeoutMillis</span></code></a> to <code class="docutils literal"><span class="pre">20</span></code>
milliseconds:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-javascript"><div class="highlight"><pre><span></span><span class="nx">db</span><span class="p">.</span><span class="nx">adminCommand</span><span class="p">(</span> <span class="p">{</span> <span class="nx">setParameter</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">maxTransactionLockRequestTimeoutMillis</span><span class="o">:</span> <span class="mi">20</span> <span class="p">}</span> <span class="p">)</span>
</pre></div>
</div>
</div>
<p>You can also set this parameter during start-up:</p>
<div class="button-code-block">
<div class="button-row">
<a class="code-button--copy code-button" role="button">
copy</a>
</div>
<div class="copyable-code-block highlight-sh"><div class="highlight"><pre><span></span>mongod --setParameter <span class="nv">maxTransactionLockRequestTimeoutMillis</span><span class="o">=</span><span class="m">20</span>
</pre></div>
</div>
</div>
</dd></dl>

</div>
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